*!* This subquery uses the In comparison test. The inner query is computed first. *!* The query results are treated as constants from that point forward, *!* and the inner query is not rerun. This increases the *!* overall performance of an IN subquery. *!* The results are evaluated against each new row in *!* the main query. When the column value is found to *!* match, or not match when a NOT IN is used, the row is *!* included in the result. If there is a non match, the row *!* is excluded.