The ANSI SQL function ... in (select destype from proclib.delay where march.Flight=delay.Flight); The subquery resolves by substituting every value for MARCH.Flight into the subquery's WHERE clause, ...

Note: This example uses a Version 6 view descriptor ... query and just to access VLIB.ALLEMP a second time in the subquery, as if the query were written: %let dept='ACC%'; proc sql stimer; select ...