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Posted by Johnny on 10/12/99 11:59
"Johnny" <removethis.huuanito@hotmail.com> wrote in message
news:YTTSg.465$UJ2.42@fed1read07...
>
> "Johnny" <removethis.huuanito@hotmail.com> wrote in message
> news:MATSg.464$UJ2.159@fed1read07...
> >
> > "Tony Louazι" <tlouaze@noos.fr> wrote in message
> > news:451bbcfc$0$17446$79c14f64@nan-newsreader-07.noos.net...
> > > Hi, My SQL lessons are very far :(
> > >
> > > CREATE TABLE CONTACTS
> > > (ID INT,
> > > NAME VARCHAR(10)
> > > PHONE VARCHAR(10))
> > >
> > > CREATE TABLE CLASS
> > > (CONTACT INT,
> > > CAT INT)
> > >
> > > INSERT INTO CONTACTS VALUES (101, 'toto', '3545')
> > > INSERT INTO CONTACTS VALUES (102, 'pif', '8421')
> > > INSERT INTO CONTACTS VALUES (103, 'loulou', '1245')
> > >
> > > INSERT INTO CLASS VALUES (101, 1)
> > > INSERT INTO CLASS VALUES (101, 2)
> > > INSERT INTO CLASS VALUES (102, 1)
> > >
> > > toto owns to category 1 and 2
> > > pif owns to category 1
> > > loulou owns to none categories
> > >
> > > => how can I display contacts who own to none categories (like loulou)
?
> > >
> > > I tried:
> > > SELECT * FROM contacts LEFT OUTER JOIN class ON id = contact
> > > I get the list of all contacts...
> > > but if I add 'WHERE cat = NULL' : there's no result :(
> > >
> > > Thanx for your help !
> > >
> > >
> >
> > isn't that what you'd expect? there don't seem to be any null cats in
what
> > you show....
> >
> >
>
> oops! not enough coffee yet! wait one :-)
>
try
IS NULL
in place of
= NULL
testing for null is a special case
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