Allow "IN" SQL operator in simple queries

By Nuno Fernandes on 19 Sep 2010
This commonly used operator forces the use of advanced queries, thus lowering the "build to change". But, on the other hand, simple queries should remain "simple"...

I propose keeping simplicity of simple queries by having the "IN" SQL operator available referencing a previous query output field (thus, "IN" the values of field X returned by that query.

Example of such an expression (for a simple query condition):

SIMPLE_QUERY_ENTITY.EntityB_ID IN PreviousQuery.ENTITY_B.ID

Of course, ideally, the usual ".List.Current." part of the record list expression should be omitted since they would affect readability.
Allow it in the Aggragates too!