Re: Differentiate Between Zero-Length String and NULL Column Values

On Tue, Jan 30, 2007 at 04:32:22PM +1100, Phillip Smith wrote:
> SHAMPOO","EQUEST","401600","0.00","0.00","0.00","0.00","10.00",""
^^
> SELECT * FROM tmpstk WHERE ean = NULL;
^^^^

Along with what Michael Fuhr said in his post about equality and
NULL, Postgres doesn't treat the empty string and NULL as equivalent
(because they're not). Only Oracle has that dodgy interpretation of
SQL, as far as I know. If you want to use the empty string, you need

WHERE ean = ''

If you want instead ean to be NULL, use the traditional \N to signify
NULL on your way in, or define null some other way.

A

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