Chris Angelico wrote > On Fri, Jun 21, 2013 at 7:36 AM, David Johnston < > polobo@ > > wrote: >> SELECT input >> FROM ( SELECT unnest($1) AS input ) src >> WHERE input IS NOT NULL AND input <> '' >> LIMIT 1; > > Does this guarantee the order of the results returned? Using LIMIT > without ORDER BY is something I've learned to avoid. > > ChrisA I have thought about this and while I'm not 100% positive on the guarantee the fact the input data is small means the planner should not be re-ordering "src" in order to apply the where clause (if it would anyway...I think re-ordering may only happen during joins). To my knowledge the result of unnest returns in the same order as the array so "src" already has an implicit "ORDER BY" attached to it. It is only when return physical relation data is the order undefined. Arrays and "VALUES" both are returned in the order defined. David J. -- View this message in context: http://postgresql.1045698.n5.nabble.com/coalesce-function-tp5760161p5760342.html Sent from the PostgreSQL - general mailing list archive at Nabble.com. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
