I think that will he helpful for you, you can find it in sas help doc.
WHERE ALSO
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Selects observations from the data set that meet the conditions that you specify and any other conditions that are already in effect.
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Path
Subset Where Also
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Description
Enter a where-expression in the Enter where also clause field. A where-expression is an arithmetic or logical expression that generally consists of a sequence of operands and operators. For information about constructing a where-expression, see the documentation of the WHERE statement in the chapter on statements in SAS Language Reference: Dictionary.
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Buttons
OK
Adds the where-expression to any other where-expressions that are already in effect and applies them all to the report. It also closes the WHERE ALSO window.
Cancel
Closes the WHERE ALSO window without altering the report.