Hi David,

No one has yet mentioned the famous FPA article of May 1999 (pg 34) titled "Rushmore: Less Is More".

It looks to me like your example fits the bill and so the problem would be the index on Deleted() (*assuming* that you are running with DELETED ON).

Cheers,

Jim N

>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).