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Re^3: "undef" is not NULL and what to do about it

by runrig (Abbot)
on Feb 21, 2013 at 00:06 UTC( #1019867=note: print w/replies, xml ) Need Help??


in reply to Re^2: "undef" is not NULL and what to do about it
in thread "undef" is not NULL and what to do about it

an empty string IS a NULL. There is no difference at all.

I think the point is you can not select the data using, e.g.WHERE colname = ''.

So how do you represent unknown values? By using a default "UNKNOWN"?

Sometimes you know what the value is, and it's blank. There's just too many ways to look at it.

.

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