# Flink SQL Reserved Keywords in Confluent Cloud for Apache Flink Keywords are words that have significance in Confluent Cloud for Apache Flink®. Some keywords, like AND, CHAR, and SELECT are *reserved* and require special treatment for use as identifiers like table names, column names, and the names of built-in functions. You can use reserved words as identifiers if you quote them with backtick characters. If you want to use one of the reserved words as a field name, enclose it with backticks, for example: ```sql `DATABASES` `RAW` ``` You can use *nonreserved* keywords as identifiers without enclosing them with backticks. In the following tables, reserved keywords are shown in **bold**. Some string combinations are reserved as keywords for future use. ## Index | [A](#flink-sql-keywords-a) | [B](#flink-sql-keywords-b) | [C](#flink-sql-keywords-c) | [D](#flink-sql-keywords-d) | [E](#flink-sql-keywords-e) | |------------------------------|------------------------------|------------------------------|------------------------------|------------------------------| | [F](#flink-sql-keywords-f) | [G](#flink-sql-keywords-g) | [H](#flink-sql-keywords-h) | [I](#flink-sql-keywords-i) | [J](#flink-sql-keywords-j) | | [K](#flink-sql-keywords-k) | [L](#flink-sql-keywords-l) | [M](#flink-sql-keywords-m) | [N](#flink-sql-keywords-n) | [O](#flink-sql-keywords-o) | | [P](#flink-sql-keywords-p) | [Q](#flink-sql-keywords-q) | [R](#flink-sql-keywords-r) | [S](#flink-sql-keywords-s) | [T](#flink-sql-keywords-t) | | [U](#flink-sql-keywords-u) | [V](#flink-sql-keywords-v) | [W](#flink-sql-keywords-w) | [X](#flink-sql-keywords-x) | [Y](#flink-sql-keywords-y) | | [Z](#flink-sql-keywords-z) | | | | | ## A | A | **ABS** | ABSENT | ABSOLUTE | ACTION | |----------------|------------------|---------------------------|-------------------|-----------| | ADA | ADD | ADMIN | AFTER | **ALL** | | **ALLOCATE** | **ALLOW** | **ALTER** | ALWAYS | **AND** | | **ANALYZE** | **ANY** | APPLY | **ARE** | **ARRAY** | | ARRAY_AGG | ARRAY_CONCAT_AGG | **ARRAY_MAX_CARDINALITY** | **AS** | ASC | | **ASENSITIVE** | ASSERTION | ASSIGNMENT | **ASYMMETRIC** | **AT** | | **ATOMIC** | ATTRIBUTE | ATTRIBUTES | **AUTHORIZATION** | **AVG** | ## B | BEFORE | **BEGIN** | **BEGIN_FRAME** | **BEGIN_PARTITION** | BERNOULLI | |-------------|-------------|-------------------|-----------------------|-------------| | **BETWEEN** | **BIGINT** | **BINARY** | **BIT** | **BLOB** | | **BOOLEAN** | **BOTH** | BREADTH | **BUCKETS** | **BY** | | **BYTES** | | | | | ## C | C | **CALL** | **CALLED** | |-------------------------------------|--------------------------------------|----------------------| | **CARDINALITY** | CASCADE | **CASCADED** | | **CASE** | **CAST** | CATALOG | | CATALOG_NAME | **CATALOGS** | **CEIL** | | **CEILING** | CENTURY | CHAIN | | **CHANGELOG_MODE** | **CHAR** | **CHARACTER** | | CHARACTERISTICS | CHARACTERS | **CHARACTER_LENGTH** | | CHARACTER_SET_CATALOG | CHARACTER_SET_NAME | CHARACTER_SET_SCHEMA | | **CHAR_LENGTH** | **CHECK** | CLASS_ORIGIN | | **CLASSIFIER** | **CLOB** | **CLOSE** | | **COALESCE** | COBOL | **COLLATE** | | COLLATION | COLLATION_CATALOG | COLLATION_NAME | | COLLATION_SCHEMA | **COLLECT** | **COLUMN** | | **COLUMNS** | COLUMN_NAME | COMMAND_FUNCTION | | COMMAND_FUNCTION_CODE | **COMMENT** | **COMMIT** | | COMMITTED | **COMPACT** | **COMPILE** | | **COMPUTE** | **CONDITION** | CONDITION_NUMBER | | CONDITIONAL | **CONNECT** | CONNECTION | | CONNECTION_NAME | **CONSTRAINT** | CONSTRAINTS | | CONSTRAINT_CATALOG | CONSTRAINT_NAME | CONSTRAINT_SCHEMA | | CONSTRUCTOR | **CONTAINS** | CONTAINS_SUBSTR | | CONTINUE | **CONTINUOUS** | **CONVERT** | | **CORR** | **CORRESPONDING** | **COUNT** | | **COVAR_POP** | **COVAR_SAMP** | **CREATE** | | **CROSS** | **CUBE** | **CUME_DIST** | | **CURRENT** | **CURRENT_CATALOG** | **CURRENT_DATE** | | **CURRENT_DEFAULT_TRANSFORM_GROUP** | **CURRENT_PATH** | **CURRENT_ROLE** | | **CURRENT_ROW** | **CURRENT_SCHEMA** | **CURRENT_TIME** | | **CURRENT_TIMESTAMP** | **CURRENT_TRANSFORM_GROUP_FOR_TYPE** | **CURRENT_USER** | | **CURSOR** | CURSOR_NAME | **CYCLE** | ## D | DATA | DATABASE | **DATABASES** | **DATE** | |------------------------|-----------------------------|-----------------------|-----------------| | DATE_DIFF | DATE_TRUNC | **DATETIME** | DATETIME_DIFF | | DATETIME_INTERVAL_CODE | DATETIME_INTERVAL_PRECISION | **DAY** | DAYOFWEEK | | DAYS | DAYOFYEAR | DATETIME_TRUNC | **DEALLOCATE** | | **DEC** | DECADE | **DECIMAL** | **DECLARE** | | **DEFAULT** | DEFAULTS | DEFERRABLE | DEFERRED | | **DEFINE** | DEFINED | DEFINER | DEGREE | | **DELETE** | **DENSE_RANK** | DEPTH | **DEREF** | | DERIVED | DESC | **DESCRIBE** | DESCRIPTION | | DESCRIPTOR | **DETERMINISTIC** | DIAGNOSTICS | **DISALLOW** | | **DISCONNECT** | DISPATCH | **DISTINCT** | **DISTRIBUTED** | | **DISTRIBUTION** | DOMAIN | DOT | **DOUBLE** | | DOW | DOY | **DRAIN** | **DROP** | | **DYNAMIC** | DYNAMIC_FUNCTION | DYNAMIC_FUNCTION_CODE |
| ## E | **EACH** | **ELEMENT** | **ELSE** | **EMPTY** | ENCODING | |------------|---------------|---------------|-------------------|--------------------| | **END** | **END-EXEC** | **END_FRAME** | **END_PARTITION** | **ENFORCED** | | EPOCH | **EQUALS** | ERROR | **ESCAPE** | **ESTIMATED_COST** | | **EVERY** | **EXCEPT** | EXCEPTION | EXCLUDE | EXCLUDING | | **EXEC** | **EXECUTE** | **EXISTS** | **EXP** | **EXPLAIN** | | **EXTEND** | **EXTENDED** | **EXTERNAL** | **EXTRACT** | | ## F | **FALSE** | **FETCH** | **FILTER** | FINAL | FIRST | |-----------------|--------------|---------------|------------|-------------| | **FIRST_VALUE** | **FLOAT** | **FLOOR** | FOLLOWING | **FOR** | | **FOREIGN** | FORMAT | FORTRAN | FOUND | FRAC_SECOND | | **FRAME_ROW** | **FREE** | **FRESHNESS** | **FRIDAY** | **FROM** | | **FULL** | **FUNCTION** | **FUNCTIONS** | **FUSION** | | ## G | G | GENERAL | GENERATED | GEOMETRY | **GET** | |------------|--------------|-------------|--------------|-----------| | **GLOBAL** | GO | GOTO | **GRANT** | GRANTED | | **GROUP** | **GROUPING** | **GROUPS** | GROUP_CONCAT | | ## H | **HAVING** | **HASH** | HIERARCHY | **HOLD** | HOP | |--------------|------------|-------------|------------|-------| | **HOUR** | HOURS | | | | ## I | **IDENTITY** | **IF** | IGNORE | IMMEDIATE | IMMEDIATELY | |------------------|--------------|---------------|-----------------|---------------| | IMPLEMENTATION | ILIKE | **IMPORT** | **IN** | INCLUDE | | INCLUDING | INCREMENT | **INDICATOR** | **INITIAL** | INITIALLY | | **INNER** | **INOUT** | INPUT | **INSENSITIVE** | **INSERT** | | INSTANCE | INSTANTIABLE | **INT** | **INTEGER** | **INTERSECT** | | **INTERSECTION** | **INTERVAL** | **INTO** | INVOKER | **IS** | | ISODOW | ISOLATION | ISOYEAR | | | ## J | **JAR** | **JARS** | JAVA | **JOB** | |--------------------|-------------------------|-----------------|-----------------| | **JOBS** | **JOIN** | JSON | **JSON_ARRAY** | | **JSON_ARRAYAGG** | **JSON_EXECUTION_PLAN** | **JSON_EXISTS** | **JSON_OBJECT** | | **JSON_OBJECTAGG** | **JSON_QUERY** | **JSON_SCOPE** | **JSON_VALUE** | ## K | K | KEY | KEY_MEMBER | KEY_TYPE | |-----|-------|--------------|------------| ## L | LABEL | **LAG** | **LANGUAGE** | **LARGE** | LAST | |--------------------|-------------|----------------|-------------|----------------| | **LAST_VALUE** | **LATERAL** | **LEAD** | **LEADING** | **LEFT** | | LENGTH | LEVEL | LIBRARY | **LIKE** | **LIKE_REGEX** | | **LIMIT** | **LN** | **LOAD** | **LOCAL** | **LOCALTIME** | | **LOCALTIMESTAMP** | LOCATOR | **LOWER** | | | ## M | M | MAP | **MATCH** | MATCHED | **MATCHES** | |------------------|---------------------|------------------|----------------|----------------------| | **MATCH_NUMBER** | **MATCH_RECOGNIZE** | **MATERIALIZED** | **MAX** | MAXVALUE | | **MEASURES** | **MEMBER** | **MERGE** | MESSAGE_LENGTH | MESSAGE_OCTET_LENGTH | | MESSAGE_TEXT | **METADATA** | **METHOD** | MICROSECOND | MILLENNIUM | | MILLISECOND | **MIN** | **MINUS** | **MINUTE** | MINUTES | | MINUTE | MINVALUE | ML_PREDICT | **MOD** | **MODEL** | | **MODELS** | **MODIFIES** | **MODIFY** | **MODULE** | **MODULES** | | **MONDAY** | **MONTH** | MONTHS | MORE | **MULTISET** | | MUMPS | | | | | ## N | NAME | NAMES | NANOSECOND | **NATIONAL** | **NATURAL** | **NCHAR** | |---------------|------------|--------------|----------------|---------------|-------------| | **NCLOB** | NESTING | **NEW** | **NEXT** | **NO** | **NONE** | | **NORMALIZE** | NORMALIZED | **NOT** | **NTH_VALUE** | **NTILE** | **NULL** | | NULLABLE | **NULLIF** | NULLS | NUMBER | **NUMERIC** | | ## O | OBJECT | **OCCURRENCES_REGEX** | OCTETS | **OCTET_LENGTH** | **OF** | |-------------|-------------------------|---------------|--------------------|--------------| | **OFFSET** | **OLD** | **OMIT** | **ON** | **ONE** | | **ONLY** | **OPEN** | OPTION | OPTIONS | **OR** | | **ORDER** | ORDERING | **ORDINAL** | ORDINALITY | OTHERS | | **OUT** | **OUTER** | OUTPUT | **OVER** | **OVERLAPS** | | **OVERLAY** | OVERRIDING | **OVERWRITE** | **OVERWRITING** | | ## P | PAD | **PARAMETER** | PARAMETER_MODE | |-------------------------|----------------------------|----------------------------| | PARAMETER_NAME | PARAMETER_ORDINAL_POSITION | PARAMETER_SPECIFIC_CATALOG | | PARAMETER_SPECIFIC_NAME | PARAMETER_SPECIFIC_SCHEMA | PARTIAL | | **PARTITION** | **PARTITIONED** | **PARTITIONS** | | PASCAL | PASSING | PASSTHROUGH | | PAST | PATH | **PATTERN** | | **PER** | **PERCENT** | **PERCENTILE_CONT** | | **PERCENTILE_DISC** | **PERCENT_RANK** | **PERIOD** | | **PERMUTE** | PIVOT | PLACING | | PLAN | **PLAN_ADVICE** | PLI | | **PORTION** | **POSITION** | **POSITION_REGEX** | | **POWER** | **PRECEDES** | PRECEDING | | **PRECISION** | **PREPARE** | PRESERVE | | **PREV** | **PRIMARY** | PRIOR | | PRIVILEGES | **PROCEDURE** | **PROCEDURES** | | PUBLIC | **PYTHON** | | ## Q | **QUALIFY** | QUARTER | QUARTERS | |---------------|-----------|------------| ## R | **RANGE** | **RANK** | **RAW** | READ | |----------------------|-----------------|-----------------------|-------------------| | **READS** | **REAL** | **RECURSIVE** | **REF** | | **REFERENCES** | **REFERENCING** | **REFRESH_MODE** | **REGR_AVGX** | | **REGR_AVGY** | **REGR_COUNT** | **REGR_INTERCEPT** | **REGR_R2** | | **REGR_SLOPE** | **REGR_SXX** | **REGR_SXY** | **REGR_SYY** | | RELATIVE | **RELEASE** | **REMOVE** | **RENAME** | | REPEATABLE | REPLACE | **RESET** | RESPECT | | RESTART | RESTRICT | **RESULT** | **RETURN** | | RETURNED_CARDINALITY | RETURNED_LENGTH | RETURNED_OCTET_LENGTH | RETURNED_SQLSTATE | | RETURNING | **RETURNS** | **REVOKE** | **RIGHT** | | RLIKE | ROLE | **ROLLBACK** | **ROLLUP** | | ROUTINE | ROUTINE_CATALOG | ROUTINE_NAME | | | ROUTINE_SCHEMA | **ROW** | **ROWS** | ROW_COUNT | | **ROW_NUMBER** | **RUNNING** | | | ## S | **SAFE_CAST** | **SAFE_OFFSET** | **SAFE_ORDINAL** | |-------------------------------|-----------------------------|--------------------------| | **SATURDAY** | **SAVEPOINT** | **SCALA** | | SCALAR | SCALE | SCHEMA | | SCHEMA_NAME | **SCOPE** | SCOPE_CATALOGS | | SCOPE_NAME | SCOPE_SCHEMA | **SCROLL** | | **SEARCH** | **SECOND** | SECONDS | | SECTION | SECURITY | **SEEK** | | **SELECT** | SELF | **SENSITIVE** | | SEPARATOR | SEQUENCE | SERIALIZABLE | | SERVER | SERVER_NAME | SESSION | | **SESSION_USER** | **SET** | SETS | | **SHOW** | **SIMILAR** | SIMPLE | | SIZE | **SKIP** | **SMALLINT** | | **SOME** | SOURCE | SPACE | | **SPECIFIC** | **SPECIFICTYPE** | SPECIFIC_NAME | | **SQL** | **SQLEXCEPTION** | **SQLSTATE** | | **SQLWARNING** | SQL_BIGINT | SQL_BINARY | | SQL_BIT | SQL_BLOB | SQL_BOOLEAN | | SQL_CHAR | SQL_CLOB | SQL_DATE | | SQL_DECIMAL | SQL_DOUBLE | SQL_FLOAT | | SQL_INTEGER | SQL_INTERVAL_DAY | SQL_INTERVAL_DAY_TO_HOUR | | SQL_INTERVAL_DAY_TO_MINUTE | SQL_INTERVAL_DAY_TO_SECOND | SQL_INTERVAL_HOUR | | SQL_INTERVAL_HOUR_TO_MINUTE | SQL_INTERVAL_HOUR_TO_SECOND | SQL_INTERVAL_MINUTE | | SQL_INTERVAL_MINUTE_TO_SECOND | SQL_INTERVAL_MONTH | SQL_INTERVAL_SECOND | | SQL_INTERVAL_YEAR | SQL_INTERVAL_YEAR_TO_MONTH | SQL_LONGVARBINARY | | SQL_LONGVARCHAR | SQL_LONGVARNCHAR | SQL_NCHAR | | SQL_NCLOB | SQL_NUMERIC | SQL_NVARCHAR | | SQL_REAL | SQL_SMALLINT | SQL_TIME | | SQL_TIMESTAMP | SQL_TINYINT | SQL_TSI_DAY | | SQL_TSI_FRAC_SECOND | SQL_TSI_HOUR | SQL_TSI_MICROSECOND | | SQL_TSI_MINUTE | SQL_TSI_MONTH | SQL_TSI_QUARTER | | SQL_TSI_SECOND | SQL_TSI_WEEK | SQL_TSI_YEAR | | SQL_VARBINARY | SQL_VARCHAR | **SQRT** | | **START** | STATE | STATEMENT | | **STATIC** | **STATISTICS** | **STDDEV_POP** | | **STDDEV_SAMP** | **STOP** | **STREAM** | | **STRING** | STRING_AGG | STRUCTURE | | STYLE | SUBCLASS_ORIGIN | **SUBMULTISET** | | **SUBSET** | SUBSTITUTE | **SUBSTRING** | | **SUBSTRING_REGEX** | **SUCCEEDS** | **SUM** | | **SUNDAY** | **SUSPEND** | **SYMMETRIC** | | **SYSTEM** | **SYSTEM_TIME** | **SYSTEM_USER** | ## T | **TABLE** | **TABLES** | **TABLESAMPLE** | TABLE_NAME | |---------------------|------------------------|--------------------------|-------------------| | TEMPORARY | **THEN** | **THURSDAY** | TIES | | **TIME** | **TIMESTAMP** | TIMESTAMP_DIFF | **TIMESTAMP_LTZ** | | TIMESTAMP_TRUNC | TIMESTAMPADD | TIMESTAMPDIFF | **TIMEZONE_HOUR** | | **TIMEZONE_MINUTE** | TIME_DIFF | TIME_TRUNC | **TINYINT** | | **TO** | TOP_LEVEL_COUNT | **TRAILING** | TRANSACTION | | TRANSACTIONS_ACTIVE | TRANSACTIONS_COMMITTED | TRANSACTIONS_ROLLED_BACK | TRANSFORM | | TRANSFORMS | **TRANSLATE** | **TRANSLATE_REGEX** | **TRANSLATION** | | **TREAT** | **TRIGGER** | TRIGGER_CATALOG | TRIGGER_NAME | | TRIGGER_SCHEMA | **TRIM** | **TRIM_ARRAY** | **TRUE** | | **TRUNCATE** | **TRY_CAST** | **TUESDAY** | TUMBLE | | TYPE | | | | ## U | **UESCAPE** | UNBOUNDED | UNCOMMITTED | UNCONDITIONAL | |------------------------|--------------------------|---------------------------|------------------------| | UNDER | **UNION** | **UNIQUE** | **UNKNOWN** | | **UNLOAD** | UNNAMED | **UNNEST** | UNPIVOT | | **UPDATE** | **UPPER** | **UPSERT** | USAGE | | **USE** | **USER** | USER_DEFINED_TYPE_CATALOG | USER_DEFINED_TYPE_CODE | | USER_DEFINED_TYPE_NAME | USER_DEFINED_TYPE_SCHEMA | **USING** | UTF16 | | UTF32 | UTF8 | | | ## V | **VALUE** | **VALUES** | **VALUE_OF** | **VARBINARY** | **VARCHAR** | |-------------|--------------|----------------|-----------------|----------------| | **VARYING** | **VAR_POP** | **VAR_SAMP** | VERSION | **VERSIONING** | | VIEW | **VIEWS** | **VIRTUAL** | | | ## W | **WATERMARK** | **WATERMARKS** | **WEDNESDAY** | WEEK | WEEKS | |-----------------|------------------|-----------------|------------------|------------| | **WHEN** | **WHENEVER** | **WHERE** | **WIDTH_BUCKET** | **WINDOW** | | **WITH** | **WITHIN** | **WITHOUT** | WORK | WRAPPER | | WRITE | | | | | ## X | XML | |-------| ## Y | **YEAR** | YEARS | |------------|---------| ## Z | ZONE | |--------| ## Related content - [DDL Statements](../concepts/statements.md#flink-sql-statements) - [Flink SQL Queries](queries/overview.md#flink-sql-queries) #### NOTE This website includes content developed at the [Apache Software Foundation](https://www.apache.org/) under the terms of the [Apache License v2](https://www.apache.org/licenses/LICENSE-2.0.html).