On 2012-11-16, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: > Ryan Kelly <rpkelly22@xxxxxxxxx> writes: >> I have a question about the behavior of SRFs in the SELECT list. > > If you have more than one in a select list, the number of resulting rows > is the least common multiple of their periods, because the select list > gets cycled until they all terminate at the same time. > >> Also, I'm not sure where this difference in behavior is >> documented. > > AFAIK it's not documented. Every time it comes up there are arguments > about whether to change it, and nobody has wanted to make a permanent > commitment to this behavior by documenting it. (On the other hand, > since it's been like this since Berkeley days, it would be pretty hard > to make an adequate case for changing it and likely breaking > applications ...) > >> And yes, I understand doing this is deprecated and my results would >> probably be better achieved with LATERAL when 9.3 comes out. > > Yeah, LATERAL has a lot less semantic messiness to it. for now you can wrap generate_series in as many CTEs as you want and do a join if you need a cross-product. -- ⚂⚃ 100% natural -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
