Thanks for your answer. It's quite logical indeed... I'm new to SQL !
Does it mean that I can't query on several tables at once if some keys have a NULL value or is there another way ? What I want is one line for my peopleId 2, built with informations from several tables... Or in other words I want to get this "virtual table" and then I want to be able to scroll through every people to display each people information (sorry if my english is not clear) : +----------+------+------+ | PeopleID | zip | city | +----------+------+------+ | 1 | 1 | aaa | +----------+------+------+ | 2 | Null | Null | +----------+------+------+ | 3 | Null | Null | +----------+------+------+ | 4 | 3 | ccc | +----------+------+------+ Thanks anyway Michael A 11:05 07/12/2001 -0800, vous avez écrit : >Michael > >do the first join >people.zip = city.zip > >yo get 2 rows from people 1 and 3 > >notice there is no peopleid 2 from first join so correct answer is to retun >null > >Rick > >-----Original Message----- >From: Michaël Delorme [mailto:[EMAIL PROTECTED]] >Sent: Friday, December 07, 2001 11:00 AM >To: [EMAIL PROTECTED] >Subject: Query and join problem with null values > > >Hi guys > >I have a problem on a SQL query : I got no records selected. Below >is a sample of my 2 tables : > >**** >A table identifying people, containing their adress therefore a ZIP >code. However for some people I don't have their adress, so no ZIP code : > >Table People >+----------+------+ >| PeopleID | zip | ... >+----------+------+ >| 1 | 1 | >| 2 | Null | >| 3 | Null | >| 4 | 3 | >| ... | >+----------+------+ > >**** > Another table describe ZIP codes and cities : > >Table City >+-----+------+ >| zip | city | ... >+-----+------+ >| 1 | aaa | >| 2 | bbb | >| 3 | ccc | >| 4 | ddd | >| 5 | eee | >| ... | >+-----+------+ > >Here is my query : > >SELECT > people.peopleId, > people.zip, > city.city > >FROM > people, > city > >WHERE > people.zip = city.zip > and people.peopleId = "2"; > >I don't get any selection... wheras I expect : >+----------+------+------+ >| PeopleID | zip | city | >+----------+------+------+ >| 2 | Null | Null | >+----------+------+------+ > > >Where am I wrong ? >Thanks in advance >Michael > > >Here are the table definitions : > >CREATE TABLE `people` ( > `peopleId` tinyint(1) unsigned NOT NULL auto_increment, > `zip` varchar(255) default NULL, > PRIMARY KEY (`peopleId`) >) > >CREATE TABLE `city` ( > `zip` tinyint(1) unsigned NOT NULL auto_increment, > `city` varchar(255) default NULL, > PRIMARY KEY (`zip`) >) > > >__________________________________________ >Michael Delorme >GIS Manager >French Mediterranean Botanical Conservancy >mailto:[EMAIL PROTECTED] > >--------------------------------------------------------------------- >Before posting, please check: > http://www.mysql.com/manual.php (the manual) > http://lists.mysql.com/ (the list archive) > >To request this thread, e-mail <[EMAIL PROTECTED]> >To unsubscribe, e-mail ><[EMAIL PROTECTED]> >Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php > > --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
