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From:Alan Nilsson Date:October 30 2006 11:57pm
Subject:Re: finding NULL records
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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.

alan
Thread
finding NULL recordsAlan Nilsson31 Oct
RE: finding NULL recordsJay Blanchard31 Oct
  • Re: finding NULL recordsAlan Nilsson31 Oct
    • Re: finding NULL recordsChris31 Oct
  • Re: finding NULL recordsMartijn Tonies31 Oct
RE: finding NULL recordsJay Blanchard31 Oct
  • Re: finding NULL recordsMartijn Tonies31 Oct
RE: finding NULL recordsJay Blanchard31 Oct
  • RE: finding NULL recordsJerry Schwartz31 Oct
    • Re: finding NULL recordsMartijn Tonies31 Oct
      • Re: finding NULL recordsmizioumt15 Nov
        • RE: finding NULL recordsJerry Schwartz15 Nov
          • Re: finding NULL recordsJoerg Bruehe16 Nov
            • Re: finding NULL recordsJoerg Bruehe16 Nov
            • Re: finding NULL recordsmizioumt17 Nov
          • Re: finding NULL recordsmizioumt17 Nov