Scalar Functions in ksqlDB for Confluent Platform¶

Numeric functions¶

`ABS`¶

Since: 0.1.0

ABS(col1)

Returns the absolute value of col1.

`ACOS`¶

Since: 0.28.0

ACOS(col1)

Returns the inverse (arc) cosine of col1, in radians. Use the DEGREES function to convert the output to degrees.

This function returns NaN for any input outside [-1, 1].

`ASIN`¶

Since: 0.28.0

ASIN(col1)

Returns the inverse (arc) sine of col1, in radians. Use the DEGREES function to convert the output to degrees.

This function returns NaN for any input outside [-1, 1].

`AS_VALUE`¶

Since: 0.9.0

AS_VALUE(keyColumn)``

Copies a row’s key column into the row’s value.

Example

CREATE TABLE AGG AS
SELECT ID,           -- this is the grouping column, which is stored in the message key.
AS_VALUE(ID) AS ID2  -- this creates a copy of ID, named ID2, which is stored in the message value.
COUNT(*) AS COUNT
FROM S
GROUP BY ID;

Tip

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`ATAN`¶

Since: 0.28.0

ATAN(col1)

Returns the inverse (arc) tangent of col1, in radians. Use the DEGREES function to convert the output to degrees.

`ATAN2`¶

Since: 0.28.0

ATAN2(y, x)

Returns the inverse (arc) tangent of y / x. This is equivalent to the angle theta when Cartesian coordinates (x, y) are converted to polar coordinates (radius, theta). The returned value is in radians.

Use the DEGREES function to convert the output to degrees.

If x is zero, y / x is undefined, and this function returns the approximate value of a multiple of π/2.

`CAST`¶

Since: 0.1.0

CAST(COL0 AS BIGINT)

Converts one type to another. The following casts are supported:

From	To	Notes
any except `BYTES`	`STRING`	Converts the type to its string representation.
`VARCHAR`	`BOOLEAN`	Any string that exactly matches `true`, case-insensitive, is converted to `true`. Any other value is converted to `false`.
`VARCHAR`	`INT`, `BIGINT`, `DECIMAL`, `DOUBLE`	Converts string representation of numbers to number types. Conversion will fail if text does not contain a number or the number does not fit in the indicated type.
`VARCHAR`	`TIME`	Converts time strings to `TIME`. Conversion fails if text is not in `HH:mm:ss` format.
`VARCHAR`	`DATE`	Converts date strings to `DATE`. Conversion fails if text is not in `yyyy-MM-dd` format.
`VARCHAR`	`TIMESTAMP`	Converts datestrings to `TIMESTAMP`. Conversion fails if text is not in ISO-8601 format.
`TIMESTAMP`	`TIME`, `DATE`	Converts a `TIMESTAMP` to `TIME` or `DATE` by extracting the time or date portion of the `TIMESTAMP`.
`DATE`	`TIMESTAMP`	Converts a `DATE` to `TIMESTAMP` by setting the time portion to `00:00:00.000`
`INT`, `BIGINT`, `DECIMAL`, `DOUBLE`	`INT`, `BIGINT`, `DECIMAL`, `DOUBLE`	Convert between numeric types. Conversion can result in rounding
`ARRAY`	`ARRAY`	(Since 0.14) Convert between arrays of different element types
`MAP`	`MAP`	(Since 0.14) Convert between maps of different key and value types
`STRUCT`	`STRUCT`	(Since 0.14) Convert between structs of different field types. Only fields that exist in the target STRUCT type are copied across. Any fields in the target type that don’t exist in the source are set to `NULL`. Field name matching is case-sensitive.

Tip

See CAST in action

`CBRT`¶

Since: 0.29.0

CBRT(col1)

Returns the cube root of col1.

`CEIL`¶

Since: 0.1.0

CEIL(col1)

Returns the the smallest integer value that’s greater than or equal to col1.

`COS`¶

Since: 0.28.0

COS(col1)

Returns the cosine of col1. col1 is in radians. Use the RADIANS function to convert the input to radians, if necessary.

`COSH`¶

Since: 0.28.0

COSH(col1)

Returns the hyperbolic cosine of col1. col1 is in radians. Use the RADIANS function to convert the input to radians, if necessary.

`COT`¶

Since: 0.28.0

COT(col1)``

Returns the cotangent of col1. col1 is in radians. Use the RADIANS function to convert the input to radians, if necessary.

This implementation returns a large value approaching positive or negative infinity near the asymptotes, because 2π and similar values cannot be represented exactly. At 0, it returns Infinity with the same sign as the input.

`DEGREES`¶

Since: 0.28.0

DEGREES(col1)

Converts col1 from radians to degrees.

`ENTRIES`¶

Since: 0.6.0

ENTRIES(map MAP, sorted BOOLEAN)

Creates an array of structs from the entries in a map. Each struct has a field named K containing the key, which is a string, and a field named V, which holds the value.

If sorted is true, the entries are sorted by key.

`EXP`¶

Since: 0.6.0

EXP(col1)

Returns the exponential of col1, which is e raised to the power of col1.

`FLOOR`¶

Since: 0.1.0

FLOOR(col1)

Returns the largest integer value that’s less than or equal to col1.

`GENERATE_SERIES`¶

Since: 0.6.0

GENERATE_SERIES(start, end) GENERATE_SERIES(start, end, step)

Constructs an array of values between start and end, inclusive.

Parameters start and end can be an INT or BIGINT.

step, if supplied, specifies the step size. The step can be positive or negative. If not supplied, step defaults to 1. Parameter step must be an INT.

`GEO_DISTANCE`¶

Since: 0.6.0

GEO_DISTANCE(lat1, lon1, lat2, lon2, unit)

The great-circle distance between two lat-long points, both specified in decimal degrees. An optional final parameter specifies KM (the default) or miles.

`GREATEST`¶

Since: 0.20.0

GREATEST(col1, col2, …)

Returns the largest non-null value from a variable number of comparable columns.

If comparing columns of different numerical types, first use the CAST function to cast them to be of the same type.

`LEAST`¶

Since: 0.20.0

LEAST(col1, col2, …)

Returns the smallest non-null value from a variable number of comparable columns.

If comparing columns of different numerical types, first use the CAST function to cast them to be of the same type.

`LN`¶

Since: 0.6.0

LN(col1)

Returns the natural logarithm of col1, which is .

The value of col1 must be greater than 0.

`LOG`¶

Since: 0.29.0

LOG(value)
LOG(base, value)

The single-parameter version of this method returns the base 10 logarithm of the value. The two-parameter version returns the logarithm with the given base of the value.

This function returns -Infinity for any base when the value is 0. It returns NaN when the value is negative, when the base is negative, when the base is 0, or when the base is 1.

`PI`¶

Since: 0.28.0

PI()

Returns an approximate value of π.

`POWER`¶

Since: 0.29.0

POWER(base, exponent)``

Calculates the value of the base raised to the exponent.

This function returns Infinity when the result overflows the DOUBLE type.

`RADIANS`¶

Since: 0.28.0

RADIANS(col1)

Converts col1 from degrees to radians.

`RANDOM`¶

Since: 0.1.0

RANDOM()

Returns a random DOUBLE value between 0.0 and 1.0.

`ROUND`¶

Since: 0.1.0

ROUND(col1)
ROUND(col1, scale)

Rounds a value to the number of decimal places specified by scale.

If scale is negative, the value is rounded to the right of the decimal point.

Numbers equidistant to the nearest value are rounded up, in the positive direction.

If the number of decimal places is not provided, it defaults to zero.

`SIGN`¶

Since: 0.6.0

SIGN(col1)

Returns the sign of col1 as an INTEGER:

-1 if the argument is negative
0 if the argument is zero
1 if the argument is positive
null argument is null

`SIN`¶

Since: 0.28.0

SIN(col1)

Returns the sine of col1. col1 is in radians. Use the RADIANS function to convert the input to radians, if necessary.

`SINH`¶

Since: 0.28.0

SINH(col1)

Returns the hyperbolic sine of col1. col1 is in radians. Use the RADIANS function to convert the input to radians, if necessary.

`SQRT`¶

Since: 0.6.0

SQRT(col1)

Returns the square root of col.

`TAN`¶

Since: 0.28.0

TAN(col1)

Returns the tangent of col1. col1 is in radians. Use the RADIANS function to convert the input to radians, if necessary.

This implementation returns a large value approaching positive or negative infinity near the asymptotes, because π/2 and similar values cannot be represented exactly.

`TANH`¶

Since: 0.28.0

TANH(col1)

Returns the hyperbolic tangent of col1. col1 is in radians. Use the RADIANS function to convert the input to radians, if necessary.

`TRUNC`¶

Since: 0.29.0

TRUNC(col1)
TRUNC(col1, scale)

Truncates (rounds toward zero) a value to the number of decimal places specified by scale.

If scale is negative, the value is truncated to the left of the decimal point. For example, TRUNC(12345.67, -3) returns 12000.

If the number of decimal places is not provided, it defaults to zero.

Collections¶

`ARRAY`¶

Since: 0.7.0

ARRAY[exp1, exp2, …]

Constructs an array from a variable number of inputs.

All elements must be coercible to a common SQL type. For more information, see Implicit Type Coercion.

`ARRAY_CONCAT`¶

Since: 0.21.0

ARRAY_CONCAT(array1, array2)

Returns an array representing the concatenation of both input arrays.

Returns NULL if both input arrays are NULL. If only one argument is NULL, the result is the other argument.

Example

-- returns [1, 2, 3, 1, 2, 4, 1]
SELECT ARRAY_CONCAT(ARRAY[1, 2, 3, 1, 2], [4, 1]);

-- returns ['apple', 'apple', NULL, 'cherry', 'cherry']
SELECT ARRAY_CONCAT(ARRAY['apple', 'apple', NULL, 'cherry'], ARRAY['cherry']);

`ARRAY_CONTAINS`¶

Since: 0.6.0

ARRAY_CONTAINS(ARRAY[1, 2, 3], 3)

Given an array, checks if a search value is contained in the array.

Accepts any ARRAY type. The type of the second param must match the element type of the ARRAY.

Tip

See ARRAY_CONTAINS in action:

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`ARRAY_DISTINCT`¶

Since: 0.10.0

ARRAY_DISTINCT([1, 2, 3])

Returns an array of all the distinct values, including NULL if present, from the input array.

The output array elements are in order of their first occurrence in the input.

Returns NULL if the input array is NULL.

Examples

-- returns [1, 2, 3]
SELECT ARRAY_DISTINCT(ARRAY[1, 1, 2, 3, 1, 2]);

-- returns ['apple', NULL, 'cherry']
SELECT ARRAY_DISTINCT(ARRAY['apple', 'apple', NULL, 'cherry']);

`ARRAY_EXCEPT`¶

Since: 0.10.0

ARRAY_EXCEPT(array1, array2)

Returns an array of all the distinct elements from an array, except for those also present in a second array.

The order of entries in the first array is preserved but duplicates are removed.

Returns NULL if either input is NULL.

Examples

-- returns [1]
SELECT ARRAY_EXCEPT(ARRAY[1, 2, 3, 1, 2], [2, 3]);

-- returns ['apple', NULL]
SELECT ARRAY_EXCEPT(ARRAY['apple', 'apple', NULL, 'cherry'], ARRAY['cherry']);

`ARRAY_INTERSECT`¶

Since: 0.10.0

ARRAY_INTERSECT(array1, array2)

Returns an array of all the distinct elements from the intersection of both input arrays.

The order of entries in the output is the same as in the first input array.

Returns NULL if either input array is NULL.

Examples

-- returns [1, 2]
SELECT ARRAY_INTERSECT(ARRAY[1, 2, 3, 1, 2], [2, 1]);

-- returns ['apple']
SELECT ARRAY_INTERSECT(ARRAY['apple', 'apple', NULL, 'cherry'], ARRAY['apple']);

`ARRAY_JOIN`¶

Since: 0.10.0

ARRAY_JOIN(col1, delimiter)

Creates a flat string representation of all the elements contained in an array.

The elements in the resulting string are separated by the chosen delimiter, which is an optional parameter. The default is the comma character, ,.

Array elements are limited to primitive ksqlDB types only.

Tip

See ARRAY_JOIN in action:

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`ARRAY_LENGTH`¶

Since: 0.8.0

ARRAY_LENGTH(ARRAY[1, 2, 3])

Returns the number of elements in an array.

If the supplied parameter is NULL, the method returns NULL.

`ARRAY_MAX`¶

Since: 0.10.0

ARRAY_MAX(['foo', 'bar', 'baz'])

Returns the maximum value from an array of primitive elements.

Arrays of other arrays, arrays of maps, arrays of structs, or combinations of these types aren’t supported.

If the array field is NULL, or contains only NULL values, NULL is returned.

Array entries are compared according to their natural sort order, which sorts the various data types as shown in the following examples.

Examples

-- returns 2
SELECT ARRAY_MAX[-1, 2, NULL, 0];

-- returns true
SELECT ARRAY_MAX[false, NULL, true];

-- returns 'baz'
-- lower-case characters are "greater" than upper-case characters
SELECT ARRAY_MAX['Foo', 'Bar', NULL, 'baz'];

`ARRAY_MIN`¶

Since: 0.10.0

ARRAY_MIN(['foo', 'bar', 'baz'])

Returns the minimum value from an array of primitive elements.

Arrays of other arrays, arrays of maps, arrays of structs, or combinations of these types aren’t supported.

If the array field is NULL, or contains only NULL values, NULL is returned.

Array entries are compared according to their natural sort order, which sorts the various data types as shown in the following examples.

Examples

-- returns -1
SELECT ARRAY_MIN[-1, 2, NULL, 0];

-- returns false
SELECT ARRAY_MIN[false, NULL, true];

-- returns 'Bar'
SELECT ARRAY_MIN['Foo', 'Bar', NULL, 'baz'];

`ARRAY_REMOVE`¶

Since: 0.11.0

ARRAY_REMOVE(array, element)

Removes all elements from array that are equal to element.

If the array field is NULL, NULL is returned.

Examples

-- returns [1, 3, 1]
SELECT ARRAY_REMOVE([1, 2, 3, 2, 1], 2);

-- returns [NULL, true, true]
SELECT ARRAY_REMOVE([false, NULL, true, true], false);

-- returns ['Foo', 'Bar', 'baz']
SELECT ARRAY_REMOVE(['Foo', 'Bar', NULL, 'baz'], null);

`ARRAY_SORT`¶

Since: 0.10.0

ARRAY_SORT(['foo', 'bar', 'baz'], 'ASC|DESC')

Given an array of primitive elements, returns an array of the same elements sorted according to their natural sort order.

Arrays of other arrays, arrays of maps, arrays of structs, or combinations of these types aren’t supported.

Any NULL values in the array are moved to the end.

If the array field is NULL, NULL is returned.

The optional second parameter specifies whether to sort the elements in ascending (ASC) or descending (DESC) order. If neither is specified, the default is ascending order.

Examples

-- returns [-1, 0, 2, NULL]
SELECT ARRAY_SORT[-1, 2, NULL, 0];

-- returns [false, true, NULL]
SELECT ARRAY_SORT[false, NULL, true];

-- returns ['Bar', 'Foo', 'baz', NULL]
SELECT ARRAY_SORT['Foo', 'Bar', NULL, 'baz'];

Tip

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`ARRAY_UNION`¶

Since: 0.10.0

ARRAY_UNION(array1, array2)

Returns an array of all the distinct elements from both input arrays, in the order they’re encountered.

Returns NULL if either input array is NULL.

Examples

-- returns [1, 2, 3, 4]
SELECT ARRAY_UNION(ARRAY[1, 2, 3, 1, 2], [4, 1]);

-- returns ['apple', NULL, 'cherry']
SELECT ARRAY_UNION(ARRAY['apple', 'apple', NULL, 'cherry'], ARRAY['cherry']);

`AS_MAP`¶

Since: 0.6.0

AS_MAP(keys, vals)

Constructs a map from a list of keys and a list of values.

Tip

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`ELT`¶

Since: 0.6.0

ELT(n INTEGER, args VARCHAR[])

Returns element n in the args list of strings, or NULL if n is less than 1 or greater than the number of arguments.

The ELT function is 1-indexed.

ELT is the complement to the FIELD function.

`FIELD`¶

Since: 0.6.0

FIELD(str VARCHAR, args VARCHAR[])

Returns the 1-indexed position of str in args, or 0 if not found.

If str is NULL, the return value is 0, because NULL isn’t considered to be equal to any value.

FIELD is the complement to the ELT function.

`JSON_ARRAY_CONTAINS`¶

Since: 0.6.0

JSON_ARRAY_CONTAINS('[1, 2, 3]', 3)

Given a STRING containing a JSON array, checks if a search value is contained in the array.

Returns false if the first parameter doesn’t contain a JSON array.

`MAP`¶

Since: 0.7.0

MAP(key VARCHAR := value, …)

Constructs a map from specific key-value tuples.

All values must be coercible to a common SQL type.

For more information, see Implicit Type Coercion.

`MAP_KEYS`¶

Since: 0.10.0

MAP_KEYS(a_map)

Returns an array that contains all keys from the specified map.

Returns NULL if the input map is NULL.

Example

-- returns ['apple', 'banana']
SELECT MAP_KEYS( MAP('apple' := 10, 'banana' := 20) );

`MAP_VALUES`¶

Since: 0.10.0

MAP_VALUES(a_map)

Returns an array that contains all values from the specified map.

Returns NULL if the input map is NULL.

Example

-- returns [10, 20]
SELECT MAP_VALUES( MAP('apple' := 10, 'banana' := 20) );

`MAP_UNION`¶

Since: 0.10.0

MAP_UNION(map1, map2)

Returns a new map containing the union of all entries from both input maps.

If a key is present in both input maps, the corresponding value from map2 is returned.

Returns NULL if all input maps are NULL.

Examples

-- returns ['apple': 10, 'banana': 20, 'cherry': 99]
SELECT MAP_UNION( MAP('apple' := 10, 'banana' := 20), MAP('cherry' := 99) );

-- returns ['apple': 50, 'banana': 20]
SELECT MAP_UNION( MAP('apple' := 10, 'banana' := 20), MAP('apple' := 50) );

`SLICE`¶

Since: 0.6.0

SLICE(col1, from, to)

Slices a list based on the supplied indices.

The indices start at 1 and include both endpoints.

Invocation Functions¶

Apply lambda functions to collections.

`FILTER`¶

Since: 0.17.0

FILTER(array, x => …)
FILTER(map, (k,v) => …)

Filters a collection with a lambda function.

If the collection is an array, the lambda function must have one input argument.

If the collection is a map, the lambda function must have two input arguments.

`REDUCE`¶

Since: 0.17.0

REDUCE(array, state, (s, x) => …)
REDUCE(map, state, (s, k, v) => …)

Reduces a collection starting from an initial state.

If the collection is an array, the lambda function must have two input arguments.

If the collection is a map, the lambda function must have three input arguments.

If the state is NULL, the result is NULL.

`TRANSFORM`¶

Since: 0.17.0

TRANSFORM(array, x => …)
TRANSFORM(map, (k,v) => …, (k,v) => …)

Transforms a collection by using a lambda function.

If the collection is an array, the lambda function must have one input argument.

If the collection is a map, two lambda functions must be provided, and both lambdas must have two arguments: a map entry key and a map entry value.

Strings¶

`CHR`¶

Since: 0.10.0

CHR(decimal_code | utf_string)

Returns a single-character string representing the Unicode code-point described by the input.

The input parameter can be either a decimal character code or a string representation of a UTF code.

Returns NULL if the input is NULL or doesn’t represent a valid code-point.

Commonly used to insert control characters such as Tab (9), Line Feed (10), or Carriage Return (13) into strings.

Examples

-- returns 'K'
SELECT CHR(75);

-- returns 'K'
SELECT CHR('\u004b');

-- returns '好'
SELECT CHR(22909);

-- returns '好'
SELECT CHR('\u597d');

`CONCAT`¶

Since: 0.1.0

CONCAT(col1, col2, 'hello', …, col-n)
CONCAT(bytes1, bytes2, …, bytes-n)

Concatenates two or more string or bytes expressions.

Any inputs which evaluate to NULL are replaced with an empty string or bytes in the output.

Tip

See CONCAT in action:

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`CONCAT_WS`¶

Since: 0.10.0

CONCAT_WS(separator, expr1, expr2, …)

Concatenates two or more string or bytes expressions, inserting a separator string or bytes between each.

If the separator is NULL, this function returns NULL.

Any expressions which evaluate to NULL are skipped.

Example

-- returns 'apple, banana, date'
SELECT CONCAT_WS(', ', 'apple', 'banana', NULL, 'date');

`ENCODE`¶

Since: 0.10.0

ENCODE(col1, input_encoding, output_encoding)

Given a STRING that is encoded as input_encoding, encode it using the output_encoding.

The accepted input and output encodings are:

hex
utf8
ascii
base64

Throws an exception if the provided encodings are not supported.

The following example encodes a hex representation of a string to a utf8 representation.

Example

ENCODE(string, 'hex', 'utf8')

`EXTRACTJSONFIELD`¶

Since: 0.11.0

EXTRACTJSONFIELD(message, '$.log.cloud')

Given a STRING that contains JSON data, extracts the value at the specified JSONPath.

For example, given a STRING containing the following JSON:

{
   "log": {
      "cloud": "gcp836Csd",
      "app": "ksProcessor",
      "instance": 4
   }
}

EXTRACTJSONFIELD(message, '$.log.cloud') returns the STRING gcp836Csd.

If the requested JSONPath does not exist, the function returns NULL.

The result of EXTRACTJSONFIELD is always a STRING. Use CAST to convert the result to another type.

For example, CAST(EXTRACTJSONFIELD(message, '$.log.instance') AS INT) extracts the instance number from the previous JSON object as a INT.

The return type of EXTRACTJSONFIELD is STRING, so JSONPaths that select multiple elements, like those containing wildcards, aren’t supported.

Note

EXTRACTJSONFIELD is useful for extracting data from JSON when either the schema of the JSON data isn’t static or the JSON data is embedded in a row that’s encoded using a different format, for example, a JSON field within an Avro-encoded message.

If the whole row is encoded as JSON with a known schema or structure, use the JSON format and define the structure as the source’s columns.

For example, a stream of JSON objects similar to the previous example could be defined using a statement similar to the following:

CREATE STREAM LOGS (LOG STRUCT<CLOUD STRING, APP STRING, INSTANCE INT>, …)
  WITH (VALUE_FORMAT='JSON', …)

`FROM_BYTES`¶

Since: 0.21.0

FROM_BYTES(bytes, encoding)

Converts a BYTES column to a STRING in the specified encoding type.

The following list shows the supported encoding types.

hex
utf8
ascii
base64

`IS_JSON_STRING`¶

Since: 0.24.0

-- returns a Boolean
IS_JSON_STRING(json_string)

Returns true if json_string can be parsed as a valid JSON value; otherwise, false .

Examples

-- returns true
SELECT IS_JSON_STRING('[1, 2, 3]');

-- returns true
SELECT IS_JSON_STRING('{}');

-- returns true
SELECT IS_JSON_STRING('1');

-- returns true
SELECT IS_JSON_STRING('\"abc\"');

-- returns true
SELECT IS_JSON_STRING('null');

-- returns false
SELECT IS_JSON_STRING('');

-- returns false
SELECT IS_JSON_STRING('abc');

-- returns false
SELECT IS_JSON_STRING(NULL);

`JSON_ARRAY_LENGTH`¶

Since: 0.24.0

-- returns an Integer or NULL
JSON_ARRAY_LENGTH(json_string)

Parses json_string as a JSON value and returns the length of the top-level array.

Returns NULL if the string can’t be interpreted as a JSON array, for example, when the string is NULL or it doesn’t contain valid JSON, or the JSON value is not an array.

Examples

-- returns 3
SELECT JSON_ARRAY_LENGTH('[1, 2, 3]');

-- returns 3
SELECT JSON_ARRAY_LENGTH('[1, [1, [2]], 3]');

-- returns 0
SELECT JSON_ARRAY_LENGTH('[]');

-- returns NULL
SELECT JSON_ARRAY_LENGTH('{}');

-- returns NULL
SELECT JSON_ARRAY_LENGTH('123');

-- returns NULL
SELECT JSON_ARRAY_LENGTH(NULL);

-- returns NULL and logs an "Invalid JSON format" exception in the server log
SELECT JSON_ARRAY_LENGTH('abc');

`JSON_CONCAT`¶

Since: 0.24.0

-- returns a String
JSON_CONCAT(json_string1, json_string2, ...)

Given N strings, parses them as JSON values and returns a string representing their concatenation.

Concatenation rules are identical to PostgreSQL’s || operator:

If all strings deserialize into JSON objects, return an object with a union of the input keys. If there are duplicate objects, take values from the last object.
If all strings deserialize into JSON arrays, return the result of array concatenation.
If at least one of the deserialized values is not an object, convert non-array inputs to a single-element array and return the result of array concatenation.
If at least one of the input strings is NULL or can’t be deserialized as JSON, return NULL.

Similar to PostgreSQL’s || operator, this function merges only top-level object keys or arrays.

Examples

-- returns '{"a":1,"b":2}'
SELECT JSON_CONCAT('{\"a\": 1}', '{\"b\": 2}');

-- returns '{"a":{"3":4}}'
SELECT JSON_CONCAT('{\"a\": {\"5\": 6}}', '{\"a\": {\"3\": 4}}');

-- returns '{}'
SELECT JSON_CONCAT('{}', '{}');

-- returns '[1,2,3,4]'
SELECT JSON_CONCAT('[1, 2]', '[3, 4]');

-- returns '[ 1, [2], [[3]], [[[4]]] ]'
SELECT JSON_CONCAT('[1, [2]]', '[[[3]], [[[4]]]]');

-- returns '[null, null]'
SELECT JSON_CONCAT('null', 'null');

-- returns '[1,2,{"a":1}]'
SELECT JSON_CONCAT('[1, 2]', '{\"a\": 1}');

-- returns '[1, 2, 3]'
SELECT JSON_CONCAT('[1, 2]', '3');

-- returns '[1, 2]'
SELECT JSON_CONCAT('1', '2');

-- returns '[]'
SELECT JSON_CONCAT('[]', '[]');

-- returns NULL
SELECT JSON_CONCAT('abc', '[1]');

-- returns NULL
SELECT JSON_CONCAT(NULL, '[1]');

`JSON_KEYS`¶

Since: 0.24.0

-- returns Array<String>
JSON_KEYS(json_string)

Parses json_string as a JSON object and returns an array of strings representing the top-level keys.

Returns NULL if the string can’t be interpreted as a JSON object, for example, when the string is NULL or it does not contain valid JSON, or the JSON value is not an object.

Examples

-- returns ['a', 'b', 'd']
SELECT JSON_KEYS('{\"a\": \"abc\", \"b\": { \"c\": \"a\" }, \"d\": 1}');

-- returns []
SELECT JSON_KEYS('{}');

-- returns NULL
SELECT JSON_KEYS('[]');

-- returns NULL
SELECT JSON_KEYS('123') => NULL JSON_KEYS(NULL);

-- returns NULL
SELECT JSON_KEYS('');

`JSON_RECORDS`¶

Since: 0.24.0

-- returns Map<String, String>
JSON_RECORDS(json_string)

Parses json_string as a JSON object and returns a map representing the top-level keys and values.

Returns NULL if the string can’t be interpreted as a JSON object, for example, when the string is NULL or it does not contain valid JSON, or the JSON value is not an object.

Examples

-- returns {d=1, a="abc", b={"c":"a"}}
SELECT JSON_RECORDS('{\"a\": \"abc\", \"b\": { \"c\": \"a\" }, \"d\": 1}');

-- returns {}
SELECT JSON_RECORDS('{}');

-- returns NULL
SELECT JSON_RECORDS('[]');

-- returns NULL
SELECT JSON_RECORDS('123');

-- returns NULL
SELECT JSON_RECORDS(NULL);

-- returns NULL
SELECT JSON_RECORDS('abc');

`JSON_ITEMS`¶

Since: 0.29.0

-- returns Array<String>
JSON_ITEMS(json_string)

Given a string with JSON array, converts it to a ksqlDB array of JSON strings.

Returns NULL if the string can’t be interpreted as a JSON array, for example, when the string is NULL or it does not contain valid JSON, or the JSON value is not an array.

Examples

-- returns ["{\"type\": \"A\", \"ts\": \"2022-01-27\"}", "{\"type\": \"B\", \"ts\": \"2022-05-18\"}"]
SELECT JSON_ITEMS('[{\"type\": \"A\", \"ts\": \"2022-01-27\"}, {\"type\": \"B\", \"ts\": \"2022-05-18\"}]');

-- returns []
SELECT JSON_ITEMS('[]');

-- returns ["1","2","3"]
SELECT JSON_ITEMS('[1, 2, 3]');

-- returns NULL
SELECT JSON_ITEMS(NULL);

-- returns NULL
SELECT JSON_ITEMS('abc');

`TO_JSON_STRING`¶

Since: 0.24.0

-- returns a String
TO_JSON_STRING(val)

Given any ksqlDB type, returns the equivalent JSON string.

Examples for primitives types

-- returns '1'
SELECT TO_JSON_STRING(1);

-- returns '15.3'
SELECT TO_JSON_STRING(15.3);

-- returns '"abc"'
SELECT TO_JSON_STRING('abc');

-- returns 'true'
SELECT TO_JSON_STRING(true);

-- returns '"2021-10-11"'
SELECT TO_JSON_STRING(PARSE_DATE('2021-10-11', 'yyyy-MM-dd'));

-- returns '"13:25"'
SELECT TO_JSON_STRING(PARSE_TIME('13:25', 'HH:mm'));

-- returns '"2021-06-30T12:18:39.446"'
SELECT TO_JSON_STRING(PARSE_TIMESTAMP('2021-06-31 12:18:39.446', 'yyyy-MM-dd HH:mm:ss.SSS'));

-- returns 'null'
SELECT TO_JSON_STRING(NULL);

Examples for compound types

-- returns '[1, 2, 3]'
SELECT TO_JSON_STRING(Array[1, 2, 3]);

-- returns '{"ID":1,"NAME":"A"}'
SELECT TO_JSON_STRING(Struct(id := 1, name := 'A'));

-- returns '{"c": 2, "d": 4}'
SELECT TO_JSON_STRING(Map('c' := 2, 'd' := 4));

-- returns '[{"JSON_KEY": 1, "JSON_VALUE": {"c": 2, "d": 3}}]'
SELECT TO_JSON_STRING(Array[Struct(json_key := 1, json_value := Map('c' := 2, 'd' := 3))]);

`INITCAP`¶

Since: 0.6.0

INITCAP(col1)

Capitalizes the first letter in each word and converts all other letters to lowercase.

Words are delimited by whitespace.

`INSTR`¶

Since: 0.10.0

INSTR(string, substring, [position], [occurrence])

Returns the position of substring in string.

The first character is at position 1.

If position is provided, search starts from the specified position.

A negative value for position causes the search to work from the end to the start of string.

If occurrence is provided, the position of the n-th occurrence is returned.

If substring is not found, the return value is 0.

Examples

-- returns  2
SELECT INSTR('CORPORATE FLOOR', 'OR');

-- returns 5
SELECT INSTR('CORPORATE FLOOR', 'OR', 3);

-- returns 14
SELECT INSTR('CORPORATE FLOOR', 'OR', 3, 2);

-- returns 5
SELECT INSTR('CORPORATE FLOOR', 'OR', -3);

-- returns 2b
SELECT INSTR('CORPORATE FLOOR', 'OR', -3, 2);

-- returns 0
SELECT INSTR('CORPORATE FLOOR', 'MISSING');

`LCASE`¶

Since: 0.1.0

LCASE(col1)

Converts a string to lowercase.

`LEN`¶

Since: 0.1.0

LEN(string)
LEN(bytes)

Returns the length of a STRING or the number of bytes in a BYTES value.

`LPAD`¶

Since: 0.10.0

LPAD(input, length, padding)

Pads the input string or bytes, beginning from the left, with the specified padding of the same type, until the target length is reached.

If the input is longer than length, it is truncated.

If the padding string or byte array is empty or NULL, or the target length is negative, NULL is returned.

Examples

-- returns 'BarBFoo'
SELECT LPAD('Foo', 7, 'Bar');

-- returns 'Fo'
SELECT LPAD('Foo', 2, 'Bar');

-- returns 'Ba'
SELECT LPAD('', 2, 'Bar');

-- returns '00123'
SELECT LPAD('123', 5, '0');

`MASK`¶

Since: 0.6.0

MASK(col1, 'X', 'x', 'n', '-')

Convert a string to a masked or obfuscated version of itself.

The optional arguments following the input string to be masked are the characters to be substituted for upper-case, lower-case, numeric, and other characters of the input, respectively.

If the mask characters are omitted, the default values are applied, as shown in the following example.

-- returns "Xx-Xxxx--nnn"
MASK("My Test $123");

Set a given mask character to NULL to prevent any masking of that character type.

-- returns "*y *est $111"
MASK("My Test $123", '*', NULL, '1', NULL);

`MASK_KEEP_LEFT`¶

Since: 0.6.0

MASK_KEEP_LEFT(col1, numChars, 'X', 'x', 'n', '-')

Similar to the MASK function, except that the first or left-most numChars characters aren’t masked in any way.

Example

-- returns "My Txxx--nnn"
SELECT MASK_KEEP_LEFT("My Test $123", 4);

`MASK_KEEP_RIGHT`¶

Since: 0.6.0

MASK_KEEP_RIGHT(col1, numChars, 'X', 'x', 'n', '-')

Similar to the MASK function, except that the last or right-most numChars characters aren’t masked in any way.

Example

-- returns "Xx-Xxxx-$123"
SELECT MASK_KEEP_RIGHT("My Test $123", 4);

`MASK_LEFT`¶

Since: 0.6.0

MASK_LEFT(col1, numChars, 'X', 'x', 'n', '-')

Similar to the MASK function, except that only the first or left-most numChars characters have any masking applied to them.

Example

-- returns "Xx-Xest $123"
SELECT MASK_LEFT("My Test $123", 4);

`MASK_RIGHT`¶

Since: 0.6.0

MASK_RIGHT(col1, numChars, 'X', 'x', 'n', '-')

Similar to the MASK function, except that only the last or right-most numChars characters have any masking applied to them.

Example

-- returns "My Test -nnn"
SELECT MASK_RIGHT("My Test $123", 4);

`MD5`¶

Since: 0.29.0

MD5('hash me')
MD5(col1)

Returns the hex-encoded MD5 hash of the given STRING.

`REPLACE`¶

Since: 0.6.0

REPLACE(col1, 'foo', 'bar')

Replaces all instances of a substring in a string with a new string.

Tip

See REPLACE in action:

Detect and analyze SSH attacks

`REGEXP_EXTRACT`¶

Since: 0.8.0

REGEXP_EXTRACT('.*', col1)
REGEXP_EXTRACT('(([AEIOU]).)', col1, 2)``

Extracts the first substring matched by the regular expression pattern from the input.

You can specify a capturing group number to return that specific group. If a number isn’t specified, the entire substring is returned by default.

Example

-- returns "there"
SELECT REGEXP_EXTRACT("(.*) (.*)", 'hello there', 2);

`REGEXP_EXTRACT_ALL`¶

Since: 0.10.0

REGEXP_EXTRACT_ALL('.*', col1)
REGEXP_EXTRACT_ALL('(([AEIOU]).)', col1, 2)``

Extracts all subtrings matched by the regular expression pattern from the input.

You can specify a capturing group number to return that specific group. If a number isn’t specified, the entire substring is returned by default.

Example

-- returns ["there", "day"]
SELECT REGEXP_EXTRACT("(\\w+) (\\w+)", "hello there nice day", 2);

`REGEXP_REPLACE`¶

Since: 0.10.0

REGEXP_REPLACE(col1, 'a.b+', 'bar')

Replaces all matches of a regular expression in an input string with a new string.

If either the input string, the regular expression, or the new string is NULL, the result is NULL.

`REGEXP_SPLIT_TO_ARRAY`¶

Since: 0.10.0

REGEXP_SPLIT_TO_ARRAY(col1, 'a.b+')

Splits a string into an array of substrings based on a regular expression.

If there is no match, the original string is returned as the only element in the array.

If the regular expression is empty, all characters in the string are split.

If either the string or the regular expression is NULL, a NULL value is returned.

If the regular expression is found at the beginning or end of the string, or there are contiguous matches, an empty element is added to the array.

`RPAD`¶

Since: 0.10.0

RPAD(input, length, padding)

Pads the input string or bytes, starting from the end, with the specified padding of the same type, until the target length is reached.

If the input is longer than the specified target length, it is truncated.

If the padding string or byte array is empty or NULL, or the target length is negative, NULL is returned.

Examples

-- returns 'FooBarB'
SELECT RPAD('Foo', 7, 'Bar');

-- returns 'Fo'
SELECT RPAD('Foo', 2, 'Bar');

-- returns 'Ba'
SELECT RPAD('', 2, 'Bar');

`SPLIT`¶

Since: 0.6.0

SPLIT(col1, delimiter)

Splits a string into an array of substrings, or bytes into an array of subarrays, based on a delimiter.

If the delimiter isn’t found, the original string or byte array is returned as the only element in the array.

If the delimiter is empty, every character in the string or byte in the array is split.

If the delimiter is found at the beginning or end of the string or bytes, or there are contiguous delimiters, an empty space is added to the array.

Returns NULL if either parameter is NULL.

Tip

See SPLIT in action:

Detect and analyze SSH attacks

`SPLIT_TO_MAP`¶

Since: 0.10.0

SPLIT_TO_MAP(input, entryDelimiter, kvDelimiter)

Splits a string into key-value pairs and creates a map from them.

The entryDelimiter splits the string into key-value pairs which are then split by kvDelimiter.

If the same key is present multiple times in the input, the latest value for the key is returned.

Returns NULL if the input text is NULL.

Returns NULL if either of the delimiters is NULL or an empty string.

Example

-- returns { 'apple':'green', 'cherry':'red'}
SELECT SPLIT_TO_MAP('apple':='green'/'cherry':='red', '/', ':=');

`SUBSTRING`¶

Since: 0.1.0

SUBSTRING(str, pos, [len])
SUBSTRING(bytes, pos, [len])

Returns the portion of str or bytes that starts at pos and has length len, or continues to the end of the string or bytes.

The first character or byte is at position 1.

Example

-- returns "stre"
SUBSTRING("stream", 1, 4);

`TO_BYTES`¶

Since: 0.21.0

TO_BYTES(string, encoding)

Converts a STRING column in the specified encoding type to a BYTES column.

The following list shows the supported encoding types.

hex
utf8
ascii
base64

`TRIM`¶

Since: 0.1.0

TRIM(col1)

Removes the spaces from the beginning and end of a string.

`UCASE`¶

Since: 0.1.0

UCASE(col1)

Converts a string to uppercase.

Tip

See UCASE in action:

Handle corrupted data from Salesforce

`UUID`¶

Since: 0.10.0

UUID()
UUID(bytes)

Creates a Universally Unique Identifier (UUID) generated according to RFC 4122.

A call to UUID() returns a value conforming to UUID version 4, sometimes called “random UUID”, as described in RFC 4122.

A call to UUID(bytes) returns a value conforming to UUID.

The value is a 128-bit number represented as a string of five hexadecimal numbers, aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee, for example, 237e9877-e79b-12d4-a765-321741963000.

Bytes¶

`BIGINT_FROM_BYTES`¶

Since: 0.23.1

BIGINT_FROM_BYTES(col1, [byteOrder])

Converts a BYTES value to a BIGINT value according to the specified byte order.

BYTES must be 8 bytes long, or a NULL value is returned.

Byte order values must be BIG_ENDIAN or LITTLE_ENDIAN. If omitted, BIG_ENDIAN is used.

A NULL value is returned if an invalid byte order value is provided.

Example, where b is a BYTES value represented as a base64 string AAAAASoF8gA=:

-- returns 5000000000
SELECT BIGINT_FROM_BYTES(b, 'BIG_ENDIAN');

`DOUBLE_FROM_BYTES`¶

Since: 0.23.1

DOUBLE_FROM_BYTES(col1, [byteOrder])

Converts a BYTES value to a DOUBLE value according to the specified byte order.

BYTES must be 8 bytes long, or a NULL value is returned.

Byte order values must be BIG_ENDIAN or LITTLE_ENDIAN. If omitted, BIG_ENDIAN is used.

A NULL value is returned if an invalid byte order value is provided.

Example, where b is a BYTES value represented as a base64 string QICm/ZvJ9YI=:

-- returns 532.8738323
SELECT DOUBLE_FROM_BYTES(b, 'BIG_ENDIAN');

`INT_FROM_BYTES`¶

Since: 0.23.1

INT_FROM_BYTES(col1, [byteOrder])

Converts a BYTES value to an INT value according to the specified byte order.

BYTES must be 4 bytes long, or a NULL value is returned.

Byte order values must be BIG_ENDIAN or LITTLE_ENDIAN. If omitted, BIG_ENDIAN is used.

A NULL value is returned if an invalid byte order value is provided.

Example, where b_big is a BYTES value represented as a base64 string AAAH5Q==:

-- returns 2021
SELECT INT_FROM_BYTES(b, 'BIG_ENDIAN');

`TO_BYTES`¶

Since: 0.21.0

TO_BYTES(col1, encoding)

Converts a STRING value in the specified encoding to BYTES.

The following list shows the supported encoding types.

hex
utf8
ascii
base64

Nulls¶

`COALESCE`¶

Since: 0.9.0

COALESCE(a, b, c, d)

Returns the first parameter that is not NULL. All parameters must be of the same type.

If the parameter is a complex type, for example, ARRAY or STRUCT, the contents of the complex type are not inspected. The behaviour is the same: the first NOT NULL element is returned.

`IFNULL`¶

Since: 0.9.0

IFNULL(expression, altValue)

If expression is NULL, returns altValue; otherwise, returns expression.

If expression evaluates to a complex type, for example, ARRAY or STRUCT, the contents of the complex type are not inspected.

`NULLIF`¶

Since: 0.19.0

NULLIF(expression1, expression2)

Returns NULL if expression1 is equal to expression2; otherwise, returns expression1.

If expression evaluates to a complex type, for example, ARRAY or STRUCT, the contents of the complex type are not inspected.

Date and time¶

`CONVERT_TZ`¶

Since: 0.17.0

CONVERT_TZ(col1, 'from_timezone', 'to_timezone')

Converts a TIMESTAMP value from from_timezone to to_timezone.

The from_timezone and to_timezone parameters are java.util.TimeZone ID formats, for example:

“UTC”
“America/Los_Angeles”
“PDT”
“Europe/London”

For more information on timestamp formats, see DateTimeFormatter.

`DATEADD`¶

Since: 0.20.0

DATEADD(unit, interval, col0)

Adds an interval to a date.

Intervals are defined by an integer value and a supported time unit.

`DATESUB`¶

Since: 0.20.0

DATESUB(unit, interval, col0)

Subtracts an interval from a date.

Intervals are defined by an integer value and a supported time unit.

`FORMAT_DATE`¶

Since: 0.20.0

FORMAT_DATE(date, 'yyyy-MM-dd')

Converts a DATE value into a string that represents the date in the specified format.

You can escape single-quote characters in the timestamp format by using two successive single quotes, '', for example: 'yyyy-MM-dd''T'''.

`FORMAT_TIME`¶

Since: 0.20.0

FORMAT_TIME(time, 'HH:mm:ss.SSS')

Converts a TIME value into the string representation of the time in the given format.

You can escape single-quote characters in the time format by using two successive single quotes, '', for example: '''T''HH:mm:ssX'.

For more information on time formats, see DateTimeFormatter.

`FORMAT_TIMESTAMP`¶

Since: 0.17.0

FORMAT_TIMESTAMP(timestamp, 'yyyy-MM-dd HH:mm:ss.SSS' [, TIMEZONE])

Converts a TIMESTAMP value into the string representation of the timestamp in the specified format.

You can escape single-quote characters in the timestamp format by using two successive single quotes, '', for example: 'yyyy-MM-dd''T''HH:mm:ssX'.

The optional TIMEZONE parameter is a java.util.TimeZone ID format, for example:

“UTC”
“America/Los_Angeles”
“PDT”
“Europe/London”

Note

To use the FORMAT_TIMESTAMP function with a BIGINT millisecond timestamp parameter, convert the millisecond value to a TIMESTAMP by using the FROM_UNIXTIME function, for example:

FORMAT_TIMESTAMP(FROM_UNIXTIME(unix_timestamp))

For more information on timestamp formats, see DateTimeFormatter.

Tip

See FORMAT_TIMESTAMP in action:

`FROM_DAYS`¶

Since: 0.20.0

FROM_DAYS(days)

Converts an INT number of days since epoch to a DATE value.

`FROM_UNIXTIME`¶

Since: 0.17.0

FROM_UNIXTIME(milliseconds)

Converts a BIGINT millisecond timestamp value into a TIMESTAMP value.

Tip

See FROM_UNIXTIME in action:

Analyze datacenter power usage

`PARSE_DATE`¶

Since: 0.20.0

PARSE_DATE(col1, 'yyyy-MM-dd')

Converts a string representation of a date in the specified format into a DATE value.

You can escape single-quote characters in the timestamp format by using two successive single quotes, '', for example: 'yyyy-MM-dd''T'''.

`PARSE_TIME`¶

Since: 0.20.0

PARSE_TIME(col1, 'HH:mm:ss.SSS')

Converts a string value in the specified format into a TIME value.

You can escape single-quote characters in the time format by using successive single quotes, '', for example: '''T''HH:mm:ssX'.

For more information on time formats, see DateTimeFormatter.

`PARSE_TIMESTAMP`¶

Since: 0.17.0

PARSE_TIMESTAMP(col1, 'yyyy-MM-dd HH:mm:ss.SSS' [, TIMEZONE])

Converts a string value in the given format into the TIMESTAMP value.

You can escape single-quote characters in the timestamp format by using successive single quotes, '', for example: 'yyyy-MM-dd''T''HH:mm:ssX'.

The optional TIMEZONE parameter is a java.util.TimeZone ID format, for example:

“UTC”
“America/Los_Angeles”
“PDT”
“Europe/London”

`TIMEADD`¶

Since: 0.20.0

TIMEADD(unit, interval, COL0)

Adds an interval to a TIME.

Intervals are defined by an integer value and a supported time unit.

`TIMESUB`¶

Since: 0.20.0

TIMESUB(unit, interval, COL0)

Subtracts an interval from a TIME.

Intervals are defined by an integer value and a supported time unit.

`TIMESTAMPADD`¶

Since: 0.17.0

TIMESTAMPADD(unit, interval, COL0)

Adds an interval to a TIMESTAMP.

Intervals are defined by an integer value and a supported time unit.

`TIMESTAMPSUB`¶

Since: 0.17.0

TIMESTAMPSUB(unit, interval, COL0)

Subtracts an interval from a TIMESTAMP.

Intervals are defined by an integer value and a supported time unit.

`UNIX_DATE`¶

Since: 0.6.0

UNIX_DATE([date])

If UNIX_DATE is called with the date parameter, the function returns the DATE value as an INTEGER value representing the number of days since 1970-01-01.

If the date parameter is not provided, the function returns an integer representing days since 1970-01-01.

Important

The returned integer may differ depending on the local time of different ksqlDB Server instances.

`UNIX_TIMESTAMP`¶

Since: 0.6.0

UNIX_TIMESTAMP([timestamp])

If UNIX_TIMESTAMP is called with the timestamp parameter, the function returns the TIMESTAMP value as a BIGINT value representing the number of milliseconds since 1970-01-01T00:00:00 UTC.

If the timestamp parameter is not provided, the function returns the current UNIX timestamp in milliseconds, represented as a BIGINT.

Important

The returned BIGINT may differ depending on the local time of different ksqlDB Server instances.

URLs¶

All ksqlDB URL functions assume URI syntax defined in RFC 39386. For more information on the structure of a URI, including definitions of the various components, see Section 3 of the RFC.

For encoding and decoding, ksqlDB uses the application/x-www-form-urlencoded convention.

`URL_DECODE_PARAM`¶

Since: 0.6.0

URL_DECODE_PARAM(col1)

Unescapes the URL-param-encoded value in col1.

This is the inverse of the URL_ENCODE_PARAM function.

Example

-- returns "url encoded"
SELECT URL_DECODE_PARAM("url%20encoded");

`URL_ENCODE_PARAM`¶

Since: 0.6.0

URL_ENCODE_PARAM(col1)

Escapes the value of col1 such that it can safely be used in URL query parameters.

Note

URL_ENCODE_PARAM is not the same as encoding a value for use in the path portion of a URL.

Example

-- returns "url%20encoded"
SELECT URL_ENCODE_PARAM("url encoded");

`URL_EXTRACT_FRAGMENT`¶

Since: 0.6.0

URL_EXTRACT_FRAGMENT(url)

Extracts the fragment portion of the specified value.

Returns NULL if url is not a valid URL or if the fragment doesn’t exist.

All encoded values are decoded.

Examples

-- returns "frag"
SELECT URL_EXTRACT_FRAGMENT("http://test.com#frag");

-- returns "frag space"
SELECT URL_EXTRACT_FRAGMENT("http://test.com#frag%20space");

`URL_EXTRACT_HOST`¶

Since: 0.6.0

URL_EXTRACT_HOST(url)

Extracts the host-name portion of the specified value.

Returns NULL if url is not a valid URI according to RFC-2396.

Example

-- returns "test.com"
SELECT URL_EXTRACT_HOST("http://test.com:8080/path");

`URL_EXTRACT_PARAMETER`¶

Since: 0.6.0

URL_EXTRACT_PARAMETER(url, parameter_name)

Extracts the value of the requested parameter from the query-string of url.

Returns NULL if the parameter is not present, has no value specified for it in the query string, or url is not a valid URI.

The function encodes the parameter and decodes the output.

To get all parameter values from a URL as a single string, use URL_EXTRACT_QUERY.

Examples

-- returns "c d"
SELECT URL_EXTRACT_PARAMETER("http://test.com?a%20b=c%20d", "a b");

-- returns "bar"
SELECT URL_EXTRACT_PARAMETER("http://test.com?a=foo&b=bar", "b");

`URL_EXTRACT_PATH`¶

Since: 0.6.0

URL_EXTRACT_PATH(url)

Extracts the path from url.

Returns NULL if url is not a valid URI but returns an empty string if the path is empty.

Examples

-- returns "path/to"
SELECT URL_EXTRACT_PATH("http://test.com/path/to#a");

`URL_EXTRACT_PORT`¶

Since: 0.6.0

URL_EXTRACT_PORT(url)

Extracts the port number from url.

Returns NULL if url is not a valid URI or does not contain an explicit port number.

Example

-- returns "8080"
SELECT URL_EXTRACT_PORT("http://localhost:8080/path");

`URL_EXTRACT_PROTOCOL`¶

Since: 0.6.0

URL_EXTRACT_PROTOCOL(url)

Extracts the protocol from url.

Returns NULL if url is an invalid URI or has no protocol.

Example

-- returns "http"
SELECT URL_EXTRACT_PROTOCOL("http://test.com?a=foo&b=bar");

`URL_EXTRACT_QUERY`¶

Since: 0.6.0

URL_EXTRACT_QUERY(url)

Extracts the decoded query-string portion of url.

Returns NULL if no query-string is present or url is not a valid URI.

Example

-- returns "a=foo bar&b=baz"
SELECT URL_EXTRACT_QUERY("http://test.com?a=foo%20bar&b=baz");

Deprecated¶

`DATETOSTRING`¶

Since: 0.7.1

Deprecated since 0.20.0 (use FORMAT_DATE)

DATETOSTRING(START_DATE, 'yyyy-MM-dd')

Converts an integer representation of a date into a string representing the date in the given format. Single quotes in the timestamp format can be escaped with two successive single quotes, '', for example: 'yyyy-MM-dd''T'''. The integer represents days since epoch matching the encoding used by Connect dates.

`STRINGTODATE`¶

Since: 0.7.1

Deprecated since 0.20.0 (use PARSE_DATE)

STRINGTODATE(col1, 'yyyy-MM-dd')

Converts a string representation of a date in the given format into an integer representing days since epoch. Single quotes in the timestamp format can be escaped with two successive single quotes, '', for example: 'yyyy-MM-dd''T'''.

`STRINGTOTIMESTAMP`¶

Since: 0.7.1

Deprecated since 0.17.0 (use PARSE_TIMESTAMP)

STRINGTOTIMESTAMP(col1, 'yyyy-MM-dd HH:mm:ss.SSS' [, TIMEZONE])

Converts a string value in the given format into the BIGINT value that represents the millisecond timestamp. Single quotes in the timestamp format can be escaped with two successive single quotes, '', for example: 'yyyy-MM-dd''T''HH:mm:ssX'.

TIMEZONE is an optional parameter and it is a java.util.TimeZone ID format, for example: “UTC”, “America/Los_Angeles”, “PDT”, “Europe/London”. For more information on timestamp formats, see DateTimeFormatter.

`TIMESTAMPTOSTRING`¶

Since: 0.7.1

Deprecated since 0.17.0 (use FORMAT_TIMESTAMP)

TIMESTAMPTOSTRING(ROWTIME, 'yyyy-MM-dd HH:mm:ss.SSS' [, TIMEZONE])

Converts a BIGINT millisecond timestamp value into the string representation of the timestamp in the given format. Single quotes in the timestamp format can be escaped with two successive single quotes, '', for example: 'yyyy-MM-dd''T''HH:mm:ssX'.

TIMEZONE is an optional parameter, and it is a java.util.TimeZone ID format, for example, “UTC”, “America/Los_Angeles”, “PDT”, or “Europe/London”. For more information on timestamp formats, see DateTimeFormatter.

Note

To use the `FORMAT_TIMESTAMP <#format_timestamp>`__ function with a BIGINT millisecond timestamp parameter, convert the millisecond value to a TIMESTAMP by using the FROM_UNIXTIME function, for example:

FORMAT_TIMESTAMP(FROM_UNIXTIME(unix_timestamp))

Scalar Functions in ksqlDB for Confluent Platform¶

Numeric functions¶

ABS¶

ACOS¶

ASIN¶

AS_VALUE¶

ATAN¶

ATAN2¶

CAST¶

CBRT¶

CEIL¶

COS¶

COSH¶

COT¶

DEGREES¶

ENTRIES¶

EXP¶

FLOOR¶

GENERATE_SERIES¶

GEO_DISTANCE¶

GREATEST¶

LEAST¶

LN¶

LOG¶

PI¶

POWER¶

RADIANS¶

RANDOM¶

ROUND¶

SIGN¶

SIN¶

SINH¶

SQRT¶

TAN¶

TANH¶

TRUNC¶

Collections¶

ARRAY¶

ARRAY_CONCAT¶

ARRAY_CONTAINS¶

ARRAY_DISTINCT¶

ARRAY_EXCEPT¶

ARRAY_INTERSECT¶

ARRAY_JOIN¶

ARRAY_LENGTH¶

ARRAY_MAX¶

ARRAY_MIN¶

ARRAY_REMOVE¶

ARRAY_SORT¶

ARRAY_UNION¶

AS_MAP¶

ELT¶

FIELD¶

JSON_ARRAY_CONTAINS¶

MAP¶

MAP_KEYS¶

MAP_VALUES¶

MAP_UNION¶

SLICE¶

Invocation Functions¶

FILTER¶

REDUCE¶

TRANSFORM¶

Strings¶

CHR¶

CONCAT¶

CONCAT_WS¶

ENCODE¶

EXTRACTJSONFIELD¶

FROM_BYTES¶

IS_JSON_STRING¶

JSON_ARRAY_LENGTH¶

JSON_CONCAT¶

JSON_KEYS¶

JSON_RECORDS¶

JSON_ITEMS¶

TO_JSON_STRING¶

INITCAP¶

INSTR¶

LCASE¶

`ABS`¶

`ACOS`¶

`ASIN`¶

`AS_VALUE`¶

`ATAN`¶

`ATAN2`¶

`CAST`¶

`CBRT`¶

`CEIL`¶

`COS`¶

`COSH`¶

`COT`¶

`DEGREES`¶

`ENTRIES`¶

`EXP`¶

`FLOOR`¶

`GENERATE_SERIES`¶

`GEO_DISTANCE`¶

`GREATEST`¶

`LEAST`¶

`LN`¶

`LOG`¶

`PI`¶

`POWER`¶

`RADIANS`¶

`RANDOM`¶

`ROUND`¶

`SIGN`¶

`SIN`¶

`SINH`¶

`SQRT`¶

`TAN`¶

`TANH`¶

`TRUNC`¶

`ARRAY`¶

`ARRAY_CONCAT`¶

`ARRAY_CONTAINS`¶

`ARRAY_DISTINCT`¶

`ARRAY_EXCEPT`¶

`ARRAY_INTERSECT`¶

`ARRAY_JOIN`¶

`ARRAY_LENGTH`¶

`ARRAY_MAX`¶

`ARRAY_MIN`¶

`ARRAY_REMOVE`¶

`ARRAY_SORT`¶

`ARRAY_UNION`¶

`AS_MAP`¶

`ELT`¶

`FIELD`¶

`JSON_ARRAY_CONTAINS`¶

`MAP`¶

`MAP_KEYS`¶

`MAP_VALUES`¶

`MAP_UNION`¶

`SLICE`¶

`FILTER`¶

`REDUCE`¶

`TRANSFORM`¶

`CHR`¶

`CONCAT`¶

`CONCAT_WS`¶

`ENCODE`¶

`EXTRACTJSONFIELD`¶

`FROM_BYTES`¶

`IS_JSON_STRING`¶

`JSON_ARRAY_LENGTH`¶

`JSON_CONCAT`¶

`JSON_KEYS`¶

`JSON_RECORDS`¶

`JSON_ITEMS`¶

`TO_JSON_STRING`¶

`INITCAP`¶

`INSTR`¶

`LCASE`¶

`LEN`¶

`LPAD`¶

`MASK`¶

`MASK_KEEP_LEFT`¶

`MASK_KEEP_RIGHT`¶