HASHBUCKET ( expression )
Syntax Elements
- expression
- An optional expression that evaluates to a valid BYTE(4) row hash value.
- If expression results in a UDT, Vantage performs implicit type conversion on the UDT, provided that the UDT has an implicit cast to a predefined byte type.
- To define an implicit cast for a UDT, use the CREATE CAST statement and specify the AS ASSIGNMENT clause. For more information on CREATE CAST, see Teradata Vantage™ - SQL Data Definition Language Syntax and Examples, B035-1144.
- Implicit type conversion of UDTs for system operators and functions, including HASHBUCKET, is a Teradata extension to the ANSI SQL standard. To disable this extension, set the DisableUDTImplCastForSysFuncOp field of the DBS Control Record to TRUE.
IF expression … THEN … does not appear in the argument list HASHBUCKET returns an INTEGER value that is the highest hash bucket number. evaluates to NULL HASHBUCKET returns NULL. evaluates to a valid BYTE(4) row hash value HASHBUCKET returns the hash bucket number corresponding to the row hash value. The range of values for hash bucket numbers depends on the system setting of the hash bucket size.- If the hash bucket size is 16 bits, the hash bucket numbers can have a value from 0 to 65535.
- If the hash bucket size is 20 bits, the hash bucket numbers can have a value from 0 to 1048575.