Обсуждение: OR problems
Hello, I've been having some problems with this SELECT clause. SELECT DISTINCT ON (nom, prenom) nom, prenom, sexe, titre, type, structure.adresse, structure.boitepostal, structure.codepostal, structure.ville FROM individu, structure, fonction WHERE type = 'CT' OR type = 'CA' The DISTINCT ON bit puts the query into a flat tailspin. Why? Cheers Tony Grant -- RedHat Linux on Sony Vaio C1XD/S http://www.animaproductions.com/linux2.html Macromedia UltraDev with PostgreSQL http://www.animaproductions.com/ultra.html
Tony, The problem is not with the OR or the DISTINCT ON. You are requesting a cartesian product ot three tables. You should have a JOIN ON or a proper WHERE clause. JLL tony wrote: > > Hello, > > I've been having some problems with this SELECT clause. > > SELECT DISTINCT ON (nom, prenom) nom, prenom, sexe, titre, type, > structure.adresse, structure.boitepostal, structure.codepostal, > structure.ville > FROM individu, structure, fonction > WHERE type = 'CT' OR type = 'CA' > > The DISTINCT ON bit puts the query into a flat tailspin. Why? > > Cheers > > Tony Grant > > -- > RedHat Linux on Sony Vaio C1XD/S > http://www.animaproductions.com/linux2.html > Macromedia UltraDev with PostgreSQL > http://www.animaproductions.com/ultra.html > > ---------------------------(end of broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster
On Fri, 2002-03-22 at 19:54, Jean-Luc Lachance wrote: > The problem is not with the OR or the DISTINCT ON. > You are requesting a cartesian product ot three tables. > You should have a JOIN ON or a proper WHERE clause. OK thanks. I thougth that was it fonction is the joining table for individu and structure. Ta Tony -- RedHat Linux on Sony Vaio C1XD/S http://www.animaproductions.com/linux2.html Macromedia UltraDev with PostgreSQL http://www.animaproductions.com/ultra.html