>When you speak of SET FILTER perhaps you reminisce on the HAVING clause. In the "older" version of VFP, I believe the HAVING clause was like "SET FILTER" and WHERE a parallel of of the modern JOIN. Or more specifically, the WHERE comes into play during the selection of records and joining of tables, and HAVING affects the recordset after.
When I wrote my "explanation", I was thinking of the "version" where you use the JOIN keyword. The other SQL "version", which you describe, is something like
Select file1.field1,file1.field2 from file1, file2;
where file1.keyfield=yourvalue and file1.keyfield=file2.keyfield;
having file1.field1=yourOthervalue
However, given all the different options you have with SQL, it's always difficult to draw exact parrellells. :-)