Subqueries in TDV
You can embed one SELECT statement within another SELECT statement. The embedded SQL statement is referred to as a subquery.
TDV supports using subqueries as values. See the section
EXISTS and NOT EXISTS.
Two types of subqueries are recognized: scalar subqueries and correlated subqueries.
Some subqueries reach row returned limitations before the query that you have written is complete. In cases where the data source allows a limit larger than 10,000 rows returned for subqueries, you can use the TDV In Clause Limit For SubQuery In Update And Delete configuration parameter to increase the subquery limit. There are many data source types that have limitations on the number of rows:
• returned from a subquery
• stored in memory
• stored in a cache
that cannot be modified. You must test your specific configuration and definitions to determine what is possible.