Once you have entered the original SQL statement in the SQL Optimizer module, you can add your own alternative SQL statement. You can do this either before or after you have optimized the original SQL statement. With this feature, you can benchmark test your own SQL alternatives with the alternatives created by the SQL Optimizer. Or, you can simply test your own alternatives against the original SQL statement.
To insert your own SQL alternative
Select the original SQL statement or the alternative SQL statement most like the one you want to insert.
Create your SQL statement.
The query plan for your SQL statement is checked to see if it matches any of the query plans for the SQL alternatives or the original SQL. If it does, you will be prompted to decide whether to insert your alternative.
Note: The User-Defined SQL statements are not checked to see if they are semantically equivalent to the original SQL. When you include a User-Defined SQL in a Batch Run, be sure to check the Remarks column of Run Time pane to see if the record count for the User-Defined SQL matches the record count for the original SQL.