Hello > -----Original Message----- > From: pgsql-general-owner@xxxxxxxxxxxxxx [mailto:pgsql-general-owner@xxxxxxxxxxxxxx] On Behalf Of Andreas Kretschmer > Sent: Sonntag, 28. Februar 2016 11:30 > To: pgsql-general@xxxxxxxxxxxxxx > Subject: Re: CONCAT returns null > > Sterpu Victor <victor@xxxxxxxx> wrote: > > > Hello > > > > I have this concat: > > CONCAT(f.nrfo, '/', TO_CHAR(fd1.validfrom, 'YYYY-MM-DD'), f2.nrfo, TO_CHAR > > (fd7.validfrom, 'YYYY-MM-DD'), DATE(fd5.validto)-DATE(fd1.validfrom)) > > that works fine but when I change to this(I added a ' with '): > > ARRAY_AGG(CONCAT(f.nrfo, '/', TO_CHAR(fd1.validfrom, 'YYYY-MM-DD'), ' with ', > > f2.nrfo, TO_CHAR(fd7.validfrom, 'YYYY-MM-DD'), DATE(fd5.validto)-DATE > > (fd1.validfrom))) AS temp, > > then concat returns NULL. > > Why? I tried to add ' with '::VARCHAR and ' with '::TEXT but the result is > > still NULL. > > > > Thank you > > NULL concat with a value returns NULL. You can avoid that using > COALESCE(value, ''), that returns the value, or, if the value NULL, ''. That was my first thought, too, but: db=> select concat(null,'sssdf',null,'dfg',NULL); concat ---------- sssdfdfg (1 row) Bye Charles -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
