Re: References NULL field
| От | Michael Fuhr |
|---|---|
| Тема | Re: References NULL field |
| Дата | |
| Msg-id | 20060403035722.GA48847@winnie.fuhr.org обсуждение |
| Ответ на | References NULL field (Paul M Foster <paulf@quillandmouse.com>) |
| Список | pgsql-sql |
On Sun, Apr 02, 2006 at 11:43:34PM -0400, Paul M Foster wrote: > I want to do a query (in PHP, FWIW) that returns all the fields in > registrars, and the contents of any relevant notes records, or null for > those fields if there is no corresponding record in the notes table. But > when I do > > SELECT * FROM registrars, notes WHERE regname = 'blah' > > no matter that I put after the 'blah' (or nothing), I get no results. As > soon as I add notes into the tables being queried, I get nothing. The above query does a cross (cartesian) join of registrars and notes. Since notes is empty the join result is empty. Try an outer join: SELECT * FROM registrars LEFT OUTER JOIN notes USING (note_id) WHERE regname = 'blah'; -- Michael Fuhr
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