Null Date
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I have a query that is looking at two dates, Case when Date A > Date B, Date A, Else B. This works fine as long as one is not null, I have tweaked my case statement to fix this, that was simple enough, what I would like to know is why does SQL not understand toss out the null date and default to the non null date?
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Because NULL is not equal to 1900/01/01. NULL is not even equal to NULL.
May I suggest a default value of the parameter in the proc? That would simplify the case statement a bit.
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Basically, NULL means 'I don't know what this value is'. If you don't know what the value is, how can you compare it (, =, =>, =<, etc) to another value?
-SQLBill
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And, you still need to determine.... is null a date way back in the past or a date in the future?
--Jeff Moden
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Exactly the point of a NULL. We don't know the information.
Now we could get started on the fact that we could know that this information does not exists but that's another story
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