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Using a field from derived table in Where issue
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Forum:
Visual FoxPro
Catégorie:
Autre
Titre:
Using a field from derived table in Where issue
Versions des environnements
Visual FoxPro:
VFP 9 SP1
Divers
Thread ID:
01521189
Message ID:
01521189
Vues:
96
Hi,

I can't seem to understand how to deal with the following issue.

I have a SQL Select that uses derived table that creates a column, e.g. TOT_QTY. If there are no records in the LEFT JOIN (derived table) the value set to TOT_QTY is null. So in the SQL Select I use NVL( TOT_QTY, 0 ). And when I look at the resulting query I see that the records from the derived table are included with the value assigned to TOT_QTY as 0. So far so good. But if I include this column name in the WHERE clause (e.g. WHERE TOT_QTY > 0) none of the records are included in the query. It looks like the WHERE always uses the NULL value of the TOT_QTY and not the one that has been "processed" by NVL(). I hope my explanation is clear. What can I do to make the WHERE work in this case? TIA.
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