Subqueries used in the subquery comparison test and set membership test both return data values from the subquery table. Sometimes, however, you may be more concerned with whether the subquery returns any results, rather than which results. The existence test (EXISTS) checks whether a subquery produces any rows of query results. If the subquery produces one or more rows of results, the EXISTS test returns TRUE. Otherwise, it returns FALSE.
Discuss this page in DocCommentXchange.
|Copyright © 2012, iAnywhere Solutions, Inc. - SQL Anywhere 12.0.1|