Re: if statement

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От Ludwig Lim
Тема Re: if statement
Дата
Msg-id 20021022005718.27079.qmail@web80314.mail.yahoo.com
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Ответ на if statement  ("Devinder K Rajput" <Devinder.Rajput@ipaper.com>)
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--- Devinder K Rajput <Devinder.Rajput@ipaper.com>
wrote:
> Hi,
>
> I am trying to find out how to do an if
> statement/case statement inside a
> select.  I am comparing item records to find out
> what is different.  Rather
> than writing a query for comparing each field
> separately, I just want to
> tell which field is different by printing the name
> of that field.  Thank
> you.

  Use the CASE clause, it simulates the if-then-else
statement in SQL.

Try the following:
  SELECT a.number,
         a.description_1,
         a.description_2,
         ....
         ....
         CASE
           WHEN a.description_1 <> b.description_1
THEN
              'description_1'
           WHEN a.description_2 <> b.description_2
THEN
              'description_2'
           /* Some more WHEN-THEN statements.... */
         END
   FROM .....
   WHERE .....


regards,
ludwig.


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