RE: Correlated Subquries

The first item for understanding subqueries of any type is to understand how joins are performed in the first place. You have several choices: nested loop, sort merge, and hash. These are discussed in the Tutorial manual and even more so in the Informix SQL course (I used to teach it). Once you understand how a join is performed, it is much easier to understand how a subquery or correlated subquery functions. Just my two-cents. Troy