NYCPHP Meetup

[Alberto dos Santos]

Dan. Thanks for your tip, but it doesn't seem to work.
If i use your code, it returns me all of catalog_reading contents, meaning I
do not have any null values on my tested table.

On the other hand, if I say NOT NULL, it returns all the lines of
catalog_reading that are present on the tested table. It's nice, but not at
all what I need ;)

Any other thoughts?

Cheers


--
Alberto dos Santos
email: acas at sapo.pt
web: otrebla.no.sapo.pt
skype: fatflash
msn: fatflash at hotmail.com
 
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-----Original Message-----
From: talk-bounces at lists.nyphp.org [mailto:talk-bounces at lists.nyphp.org] On
Behalf Of Dan Cech
Sent: quarta-feira, 22 de Junho de 2005 12:42
To: NYPHP Talk
Subject: Re: [nycphp-talk] Still Mysql Selects

Alberto dos Santos wrote:
> I have a table called "CATALOG_READING" with two entries, one is the ID
> (CR_ID) and the other a value.
> Then I have 16 tables each with 4 rows that have a value from CR_ID, in
> order to use the values from the CATALOG_READING table in different
> situations.
> 
> What I need to check is which values from CR_ID are NOT USED in any of the
> other tables, so I can identify and remove it.

SELECT c.cr_id
FROM catalog_reading AS c
LEFT JOIN table_x AS x ON x.cr_id=c.cr_id
LEFT JOIN table_y AS y ON y.cr_id=c.cr_id
LEFT JOIN table_z AS z ON z.cr_id=c.cr_id
...
WHERE x.cr_id IS NULL
AND y.cr_id IS NULL
AND z.cr_id IS NULL
...

Give something like that a shot.

Dan
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