Hash Functions in Confluent Cloud for Apache Flink

Confluent Cloud for Apache Flink® provides these built-in functions to generate hash codes in SQL queries:

MD5

Gets the MD5 hash of a string.

Syntax
MD5(string)
Description

The MD5 function returns the MD5 hash of the specified string as a string of 32 hexadecimal digits.

Returns NULL if string is NULL.

Example
-- returns 99dc0ea422440e5b3f675cffe6d...
SELECT MD5('string-to-hash');

SHA1

Gets the SHA-1 hash of a string.

Syntax
SHA1(string)
Description

The SHA1 function returns the SHA-1 hash of the specified string as a string of 40 hexadecimal digits.

Returns NULL if string is NULL.

Example
-- returns 771a2b04044f8c51e3383a2675a...
SELECT SHA1('string-to-hash');

SHA2

Hashes a string with one of the SHA-2 functions.

Syntax
SHA2(string, hashLength)
Description

The SHA2 function returns the hash using the SHA-2 family of hash functions (SHA-224, SHA-256, SHA-384, and SHA-512).

  • The first argument, string, is the string to be hashed.
  • The second argument, hashLength, is the bit length of the result.

These are the valid bit lengths for hashLength:

  • 224
  • 256
  • 384
  • 512

Returns NULL if string or hashLength is NULL.

Example
-- returns 222145560dbaa2abc1617e2c7ce...
SELECT SHA2('string-to-hash', 512);

SHA224

Gets the SHA-224 hash of a string.

Syntax
SHA224(string)
Description

The SHA224 function returns the SHA-224 hash of the specified string as a string of 56 hexadecimal digits.

Returns NULL if string is NULL.

Example
-- returns af1f1c988d9154f2ddb6201f60f...
SELECT SHA224('string-to-hash');

SHA256

Gets the SHA-256 hash of a string.

Syntax
SHA256(string)
Description

The SHA256 function returns the SHA-256 hash of the specified string as a string of 64 hexadecimal digits.

Returns NULL if string is NULL.

Example
-- returns 2267d414e45335fd02e64057d55...
SELECT SHA256('string-to-hash');

SHA384

Gets the SHA-384 hash of a string.

Syntax
SHA384(string)
Description

The SHA5384 function returns the SHA-384 hash of the specified string as a string of 96 hexadecimal digits.

Returns NULL if string is NULL.

Example
-- returns 02ba979b23f1b4a098732463ea8...
SELECT SHA384('string-to-hash');

SHA512

Gets the SHA-512 hash of a string.

Syntax
SHA512(string)
Description

The SHA512 function returns the SHA-512 hash of the specified string as a string of 128 hexadecimal digits.

Returns NULL if string is NULL.

Example
-- returns 222145560dbaa2abc1617e2c7ce...
SELECT SHA512('string-to-hash');

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