The join method SQL optimization specification allows you to specify a join method for a joined table.

Join-method-SQL-optimization-specification::= BY {NEST|HASH|MERGE}

• {NEST|HASH|MERGE}

NEST

This option can be specified when the join method is a nested-loop join.

If the inner table is a base table or a named derived table based on a base table, the join method becomes a nested-loop join.

HASH

This option can be specified when making the join method into a hash-join.

MERGE

This option can be specified when making the join method into a merge-join.

1. Specifying HASH requires the same preparations as specifying execution of a hash-join or a subquery hash for the SQL extension optimizing option. For preparations for applying either hash-join or subquery-hash-join, see the HiRDB Version 9 UAP Development Guide.

1. For join methods, see the HiRDB Version 9 UAP Development Guide. Join methods can be checked by using the access path display utility.