Improve filter selectivity

You can control the amount of information that a query evaluates. The greater the precision with which you specify the desired rows, the greater the likelihood that your queries will complete quickly.

To control the amount of information that the query evaluates, use the WHERE clause of the SELECT statement. The conditional expression in the WHERE clause is commonly called a filter.

For information about how filter selectivity affects the query plan that the optimizer chooses, see Filters in the query. The following sections provide some guidelines to improve filter selectivity.