HASHED_VALUE
The HASHED_VALUE function returns the partition map index number of a row obtained by applying the hashing function on the partitioning key value of the row.
Also see the HASH function. If the argument identifies a non-distributed table, the value 0 is returned. For more information about partition maps and partitioning keys, see the DB2® Multisystem topic collection.
- table-designator
- A table designator of the subselect. For more information about
table designators, see Table designators.
In SQL naming, the table name may be qualified. In system naming, the table name cannot be qualified.
The table-designator must not identify a collection-derived-table, a VALUES clause, a table-function, or a data-change-table-reference.
If the argument identifies a view, common table expression, or nested table expression, the function returns the partition map index number of its base table. If the argument identifies a view, common table expression, or nested table expression derived from more than one base table, the function returns the partition map index number of the first table in the outer subselect of the view, common table expression, or nested table expression.
The argument must not identify a view, common table expression, or nested table expression whose outer fullselect includes an aggregate function, a GROUP BY clause, a HAVING clause, a UNION, INTERSECT, or EXCEPT clause, DISTINCT clause, VALUES clause, or a table-function. The HASHED_VALUE function cannot be specified in a SELECT clause if the fullselect contains an aggregate function, a GROUP BY clause, or a HAVING clause
The data type of the result is a large integer with a value between 0 and 1023. The result can be null.
Note
Syntax alternatives: PARTITION is a synonym for HASHED_VALUE.
Example
- Select the employee number (EMPNO) from the EMPLOYEE table for
all rows where the partition map index number is equal to 100.
SELECT EMPNO FROM EMPLOYEE WHERE HASHED_VALUE(EMPLOYEE) = 100