Re: Case Statement - Mailing list pgsql-sql

From Stephan Szabo
Subject Re: Case Statement
Date
Msg-id 20020731160809.M21990-100000@megazone23.bigpanda.com
Whole thread Raw
In response to Case Statement  ("Tom Haddon" <tom@betterhealthfoundation.org>)
List pgsql-sql
On Wed, 31 Jul 2002, Tom Haddon wrote:

> Hi Folks,
>
> Pretty basic one here. I'm trying to do a SELECT statement that includes a
> CASE structure that will be used in the ORDER BY clause, and I want the CASE
> structure to evaluate a bunch of criteria and in each case increment its
> value by a certain amount:
>
> SELECT id, description CASE
>         field1 IS TRUE THEN CASE=CASE+1
>         field2 IS TRUE THEN CASE=CASE+2
>         END
> FROM table
> ORDER BY CASE, description;
>
> Am I misunderstanding what CASE can do here, and if so, how else do I do
> what I'm trying to do? I know that that isn't right - any pointers
> appreciated.

Are you trying to get a 0-3 based on field1 and field2 or some kind of
aggregate?  The first you can do that with something likecase when field1 is true then 1 else 0 end +case when field2
istrue then 2 else 0 end
 
I think. (Extend for more columns)

Or if you've got like 7-8 columns maybe just make a function that does
the work for you for clarity.

You'll also need a comma after description and you'll want to alias the
case expression and use that in order by or use the position number.




pgsql-sql by date:

Previous
From: "Tom Haddon"
Date:
Subject: Case Statement
Next
From: "Tom Haddon"
Date:
Subject: FW: Case Statement