We all know and love Drupal Views. The queries that it builds are most often very elegant, but there are certain cases where you need to use a query that is just a bit too complicated for the Views query generator to build on its own. I ran into this recently where I could not accomplish my task without a join to a sub-query.

If you find this to be the case, you can utilize the views_pre_execute hook to override the query being supplied by Views.