>>Hi Naomi,
>>
>>My problem was that my LEFT JOIN was missing a simple expression like Field = uVaraible, which Tamar noticed and correctly suggested. My WHERE condition has a subquery similar to what you wrote in this reply. First I thought that I needed to move the subquery to the LEFT JOIN but it is not necessary. I am going to test the changes again today to be sure I am not missing something.
>>
>>You are correct, we did discuss this issue some months ago. And I thought I had a solution back then. But a few days ago, when a certain set of data came across, I found a problem with the logic. Adding SUBQUERY to the WHERE clause, so far, seems to resolve the issue.
>>
>>I don't know what to be impressed more: with your intuition to see in the past or with Tamar's such a sharp eye that she noticed something in seconds whereas I struggled with the problem for hours yesterday. I am glad I always find myself in a group of smart women :).
>>
>
>FWIW, this is a question I struggled with when outer joins were added to VFP, so once I found the answer and understood why it has to be that way, it really stuck. It's something I've presented and written about repeatedly because it is a common problem.
>
>Tamar

I am glad you came across my question and helped me. Thank you.