On 2016-09-12 13:48:05 -0400, Tom Lane wrote: > Andres Freund <and...@anarazel.de> writes: > > On 2016-09-12 13:26:20 -0400, Tom Lane wrote: > >> Andres Freund <and...@anarazel.de> writes: > > On 2016-09-12 12:10:01 -0400, Tom Lane wrote: > >>>> I can't say that I like the proposed syntax much. > > >>> Me neither. But I haven't really found a better approach. It seems > >>> kinda consistent to have ROWS FROM (... AS ()) change the picked out > >>> columns to 0, and just return the whole thing. > > >> I just remembered that we allow zero-column composite types, which > >> makes this proposal formally ambiguous. So we really need a different > >> syntax. I'm not especially in love with the cast-to-record idea, but > >> it does dodge that problem. > > > I kind of like ROWS FROM (... AS VALUE), that seems to confer the > > meaning quite well. As VALUE isn't a reserved keyword, that'd afaik only > > really work inside ROWS FROM() where AS is required. > > Hm, wouldn't ... AS RECORD convey the meaning better?
I was kind of envisioning AS VALUE to work for composite types without removing their original type (possibly even for TYPEFUNC_SCALAR ones). That, for one, makes the SRF to ROWS FROM conversion easier, and for another seems generally useful. composites keeping their type with AS RECORD seems a bit confusing. There's also the issue that VALUE is already a keyword, record not... > (Although once you look at it that way, it's just a cast spelled in > an idiosyncratic fashion.) Well, not quite, by virtue of keeping the original type around. After a record cast you likely couldn't directly access the columns anymore, even if it were a known composite type, right? Andres -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
