Create User Defined Alternatives

SQL Optimizer for IBM DB2 z/OS

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Create User Defined Alternatives

In addition to using SQL Optimizer to generate alternative statements, you can create user defined alternatives. You can create user defined alternatives using SQL text from your original SQL statement or from SQL text of an alternative SQL Optimizer generated.

Note: This topic focuses on information that may be unfamiliar to you. It does not include all step and field descriptions.

To create a user defined alterative

Select the SQL Details tab in the main window.
Enter the SQL statement in the in the Alternative Details pane.
Click .
Edit the statement in the SQL Text pane to create a user defined alternative.

Note: To create a user defined alternative using SQL text of an alternative SQL Optimizer generated, right-click an alternative and select User Alternative.

Caution: SQL Optimizer does not check that user defined alternatives are semantically equivalent to your original SQL statement. Review the execution statistics for user defined alternatives to compare the results with your original statement. See View Execution Statistics for more information.