The subquery resolves by substituting every value for MARCH.Flight into the subquery's WHERE clause, one row at a time. For example, when MARCH.Flight= 219, the subquery resolves as follows: PROC SQL ...

As a result, you can now create a PROC SQL view, DATA step view, or SAS/ACCESS view with DBMS data. For this example you create a view descriptor, VLIB.ALLEMP, based on SYBASE data. The outer PROC SQL ...