NVL( ) is a Visual FoxPro function. It provides a way to keep nulls from propagating without having to use IsNull( ).
You can think of NVL(eExpression1,eExpression2) as shorthand for:
IIF(IsNull(eExpression1),eExpression1,eExpression2)
Syntax
NVL(eExpression1,eExpression2)
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