Re: comparing nulls

On Tue, Jan 20, 2004 at 07:13:12PM +0530, Kenneth Gonsalves wrote:
> in postgres7.1 i had a table where an integer field could be null. There was
> no default value. a select statement like so:
> 'select * from table where field = null'
> would give all the rows where that field had no value.
> on porting to 7.3.2, this doesnt work. How to do this?

Because NULL can be read as "unknown". It does not make much sense to
test wheter a value of an integer is numerically equal to unknown. That is
why there is the IS operator:

where field IS null

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"Nothing is as subjective as reality"
Reinoud van Leeuwen reinoud(dot)v(at)n(dot)leeuwen(dot)net
http://www.xs4all.nl/~reinoud
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