Re: Updates with NULL - Mailing list pgsql-general

From Manfred Koizar
Subject Re: Updates with NULL
Date
Msg-id d9lbmv0e1t2heru25jhrk5vljjafrkp79t@email.aon.at
Whole thread Raw
In response to Updates with NULL  ("Shridhar Daithankar" <shridhar_daithankar@persistent.co.in>)
Responses Re: Updates with NULL  (Dennis Gearon <gearond@fireserve.net>)
List pgsql-general
On Mon, 15 Sep 2003 19:34:48 +0530, "Shridhar Daithankar"
<shridhar_daithankar@persistent.co.in> wrote:
>Update foo set somefield=NULL where somefield >9;
>
>Now I am not sure having something equalled with NULL is a good thig logically.

It doesn't matter whether I agree.  The standard does not.  SQL92 says

         <set clause> ::=
              <object column> <equals operator> <update source>

         <equals operator> ::= =

         <update source> ::=
                <value expression>
              | <null specification>
              | DEFAULT

         <null specification> ::=
              NULL

SQL99 is much more verbose and difficult to read, but it is very clear
that the assignment operator in a set clause has to be "=".

Servus
 Manfred

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