602SQL Documentation Index  

UNIQUE Predicate

UNIQUE_predicate ::= UNIQUE ( query_expression )

The UNIQUE predicate tells whether all records in the query_expression result (subquery) have unique values. Only rows not containing the NULL value are taken into account.

Usage Example:

  IF NOT UNIQUE (SELECT id FROM PriceList) THEN CALL Log_write('Duplicates occur in the price list!!'); END IF;