SQL Query Logic / Conditional WHERE

Question

I'm hoping this is a simple question, but I can't figure out how to write my query to get the correct result!

I'm trying to translate a query from a report on our ERP solution (Dynamics NAV) into T-SQL.

I've gotten stuck with a condition of the report. In NAV, it retrieves all of the data using a set of filters - which is fine. After it retrieves the data, it goes through record by record, and 'skips' records which meet 2 conditions.

The condition for records being skipped are: If "Field A" <> 4 AND "Field B" = 0 THEN SKIP.

The closest i've got to recreating this in T-SQL is:

Select *
From t
WHERE [...] AND ( [FieldA] <> 4 AND [FieldB] = 0 )

This does not work!

How can I exclude records in T-SQL, only where ((A <> 4) AND (B = 0)) ?

Daniel Renshaw · Accepted Answer · 2013-06-11 07:35:45Z

2

The logic equivalence not(A and B) === not(A) or not(B) is appropriate here.

In this case A means "Field A" <> 4 and B means "Field B" = 0. So not(A) means "Field A" = 4 and not(B) means "Field B" <> 0.

Hence

SELECT *
FROM t
WHERE [...]
    AND
    (
        [FieldA] = 4 OR
            [FieldB] <> 0
    )

answered Jun 11, 2013 at 7:35

Daniel Renshaw

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