From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | pgsql-sql(at)postgreSQL(dot)org |
Subject: | Does SQL have anything like C's conditional expression? |
Date: | 1998-07-20 20:01:33 |
Message-ID: | 22075.900964893@sss.pgh.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-sql |
I have the following problem: given a specific record in a table
(identified by OID, in my case), always update field A to a new value,
and update field B to a new value only if field C contains 'OK'.
This is easy to do in two queries, say
UPDATE table SET fieldA = valueA WHERE oid = something;
UPDATE table SET fieldB = valueB WHERE oid = something AND fieldC = 'OK';
For speed reasons, I'm wondering if it can be done in one query.
It could be done with something like a C conditional expression:
UPDATE table SET
fieldA = valueA,
fieldB = (fieldC = 'OK') ? valueB : fieldB
WHERE oid = something;
but SQL doesn't seem to have that concept. Can anyone suggest
a fast way to do what I need to do?
regards, tom lane
From | Date | Subject | |
---|---|---|---|
Next Message | Peter T Mount | 1998-07-22 05:42:49 | Re: [SQL] Can I store bitmap graphics in a table? |
Previous Message | Dan Delaney | 1998-07-20 17:55:24 | Can I store bitmap graphics in a table? |