RE: SQL question - why doesn't WHERE clause know about renamed fields?

That's one way. Another (mentioned already, not by me) is to use CTE:

WITH T1 as
(
SELECT
numtodate(polog.poendt) as day_entered,
numtodate(ech.hedte) as day_ordered
FROM xyzlib/pologpf AS polog
LEFT JOIN xyzlib/ech AS ech
ON polog.pokord = ech.hord
)
SELECT * from T1
where day_entered+3 > day_ordered


Dennis Lovelady
http://www.linkedin.com/in/dennislovelady
--
"Genius is one per cent inspiration and ninety-nine per cent perspiration."
-- Thomas Edison

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-
bounces@xxxxxxxxxxxx] On Behalf Of Gqcy
Sent: Monday, November 08, 2010 11:44 AM
To: midrange-l@xxxxxxxxxxxx
Subject: Re: SQL question - why doesn't WHERE clause know about renamed
fields?

Thanks for the answers...
So, If I add my UDF to this discussion, I need to call it multiple
times, as shown:

SELECT
numtodate(polog.poendt) as day_entered,
numtodate(ech.hedte) as day_ordered
FROM xyzlib/pologpf AS polog
LEFT JOIN xyzlib/ech AS ech
ON polog.pokord = ech.hord
where DAYS(numtodate(polog.poendt))+3 > DAYS(numtodate(ech.hedte))



On 11/8/2010 10:31 AM, Dennis Lovelady wrote:

Sorry, Lloyd, but that's kind of like answering a "why is the sky

blue"

question by saying that the sky color contains no red or yellow. The

answer

of WHY is that the SELECT list is evaluated last, so there is no way

for the

WHERE clause to be aware of the SELECT list's rename.

Dennis Lovelady
http://www.linkedin.com/in/dennislovelady
--
"Few things are harder to put up with than the annoyance of a good

example."

-- Mark Twain

Generally, you cannot use aliased names (day_entered) in the WHERE
clause.
You need to use polog.poendt instead.

--Loyd

On Mon, Nov 8, 2010 at 10:02 AM, Gqcy<gmufasa01@xxxxxxxxx> wrote:

SELECT
polog.poendt as day_entered,
ech.hedte as day_ordered
FROM xyzlib/pologpf AS polog
JOIN xyzlib/ech AS ech
ON polog.pokord = ech.hord
where day_entered> day_ordered

Column DAY_ENTERED not in specified tables.


Is this just part of SQL, or am I missing something???

These are dates, and I have created a UDF to convert numeric
to Date(not shown in above example), but I can't use the renamed

fields...

thanks

Gerald

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