By examining the query plan, you can see exactly how the database executes your SQL statement, helping you judge whether the SQL statement is the most efficient or any changes to the table structure are needed such as adding a new index.
To view the query plan of the original SQL statement in the SQL Optimizer window
If parameters exist in the original SQL statement, you are required to define the parameters and data types of the parameters before the query plan is retrieved. Or, alternatively use the SQL | Show Default Plan to retrieve the query plan without the need to enter parameter details. Show Default Plan allows you to quickly view the query plan without the need to enter the data type variables.
For more specific information about each step of the query plan, click any text in the step and the Plan Detail window displays.