SQL problem

Can someone tell me why I get different query results when I filter with either of these two statements SQL

IIf(ExtensionType<>"","Yes","") AS Extension
IIf(ExtensionType="","","YES") AS Extension
Derek BrownMDAsked:
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ExtensionType contains nulls for some rows.  Null will not satisfy either condition.  You will need to change the expression to the following to solve the problem:

IIf(ExtensionType & "" <>"","Yes","") AS Extension

This expression concatenates a ZLS to ExtensionType.  so the argument will be a ZLS if it was originally null.

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Derek BrownMDAuthor Commented:
Thanks Pat

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