lExpression

Specifies the condition that records must satisfy. If the current table is indexed on a field or fields specified in lExpression, Rushmore Query Optimization technology can optimize queries based on the field or fields.

IN nWorkArea| cTableAlias

Specifies the work area or table alias affected by the SET FILTER command. Use this clause to specify a work area or a table outside the current work area.

Once SET FILTER is issued, only the records that satisfy the condition specified by the logical expression lExpression are available in the table. All commands that access the table respect the SET FILTER condition. A separate filter can be set for every open table.

The condition specified by SET FILTER isn't evaluated until the record pointer is moved in the table.

Issuing SET FILTER TO without lExpression turns off the filter for the current table.

SELECT – SQL does not respect the current filter condition.

Note:
When using SET FILTER to filter data in a grid, use the SET KEY command to increase grid performance.