Snowflake provides non-cryptographic hash functions, which take input value(s) and return a signed 64-bit numeric value. Hash functions are deterministic. Snowflake provides both a scalar hash function and an aggregate hash function, both of which are listed here.
- HASH()
- Returns a signed 64-bit hash value. Note that HASH never returns NULL, even for NULL inputs.
- use case:
- Convert skewed data values to values that are likely to be more randomly or more evenly distributed.
- HASH_AGG()
- Returns an aggregate signed 64-bit hash value over the (unordered) set of input rows. HASH_AGG never returns NULL, even if no input is provided. Empty input “hashes” to
0. - usecase:
- use for aggregate hash functions is to detect changes to a set of values without comparing the individual old and new values (e.g. difference of two lists)
- Returns an aggregate signed 64-bit hash value over the (unordered) set of input rows. HASH_AGG never returns NULL, even if no input is provided. Empty input “hashes” to