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Databases,Tables, Views, Indexing and SQL syntax
>Hi Albert,
>I'm not using "UNION ALL" just "UNION" so they should be equivalent.
>
>>David has the explanation of the performance difference, but are you aware that the two selects are not equivalent? The select with the union will give two rows whenever (C.Addrnum = A.Addrnum AND C.PAddrnum = A.Addrnum).
nevermind...
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