Re: How to retrieve rows with empty value in numeric(12,8) columns - Mailing list pgsql-general

From Raymond O'Donnell
Subject Re: How to retrieve rows with empty value in numeric(12,8) columns
Date
Msg-id 4EDDF784.9050704@iol.ie
Whole thread Raw
In response to Re: How to retrieve rows with empty value in numeric(12,8) columns  (Adarsh Sharma <adarsh.sharma@orkash.com>)
Responses Re: How to retrieve rows with empty value in numeric(12,8) columns  (Bèrto ëd Sèra <berto.d.sera@gmail.com>)
List pgsql-general
On 06/12/2011 11:00, Adarsh Sharma wrote:
> try
>>
>> select * from table where lat IS NULL;
>>
>> Bèrto
> :-) It works, Thanks a lot Berto !
>
> can you explain how it works or any link that explain the difference
> between 2 queries.

As I understand it, your first query returned nothing because NULL is
simply "unknown" - and since you can never know what it's equal to,
looking for equality with NULL will never find anything.

Ray.

--
Raymond O'Donnell :: Galway :: Ireland
rod@iol.ie

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