Alan Nilsson wrote:
On Oct 30, 2006, at 3:27 PM, Jay Blanchard wrote:
[snip]
I am trying to find records where the value of a filed is NULL. I
know that there are records that have null values but the result is
always an empty set.
eg:
select test_id from tests where test_id=NULL
always returns an empty set when there are in fact records that have
a null value for test_id. Is there some trick to finding null valued
records in MySQL? This same sql has always worked on any other dbms
I have used.
[/snip]
Of course this will return an empty set because you have only selected
the test_id, try this;
SELECT * FROM tests WHERE test_id IS NULL
Yes, that works, but I was also trying SELECT * instead of just the key
field (just a typo in the example). The problem was in the equal sign
versus the 'IS' operator. Any reason why MySQL does not honor
<field>=NULL? Seems kind of odd.
Sql standard says you use IS NULL.
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