Apologies for butting in but can I (as a user) express a preference as a user against DO?
Firstly, it looks horrible. And what's to stop me having "SELECT true AS do" in the where clause (as per your UPDATE objection)? Shouldn't UPDATE be a reserved keyword anyway? AIUI ANSI suggests so. http://developer.mimer.se/validator/sql-reserved-words.tml I had always assumed it was; anyone who produced a query for me that contained update in an unusual context would get slapped heavily. Geoff On 23 April 2015 at 11:54, Andres Freund <and...@anarazel.de> wrote: > On 2015-04-22 16:40:07 -0700, Peter Geoghegan wrote: > > On Wed, Apr 22, 2015 at 3:23 PM, Peter Geoghegan <p...@heroku.com> wrote: > > > * We need to sort out those issues with the grammar, since that only > > > really applies to the inference specification. Maybe the WHERE clause > > > that the inference specification accepts can be broken out. No ON > > > CONFLICT UPDATE specific issues left there, AFAICT though. > > > > I pushed some code that deals with the predicate being within > parenthesis: > > > > > https://github.com/petergeoghegan/postgres/commit/358854645279523310f998dfc9cb3fe3e165ce1e > > And the way you've used nonassoc here doesn't look correct. You're > hiding legitimate ambiguities in the grammar. UPDATE is a unreserved > keyword, so for > > ... ON CONFLICT '(' index_params ')' where_clause OnConflictUpdateStmt > > it won't be able to discern whether an UPDATE in the WHERE clause is > part of the where_clause or OnConflictUpdate. > > This is legal: > SELECT * FROM (SELECT true as update) f WHERE update; > i.e. 'update' can be the last part of a WHERE clause. > > Essentially what you're trying to do with the nonassic is hiding that > UPDATE and IGNORE need to be reserved keywords with the syntax you're > proposing. We can either make them reserved or change the syntax. > > One way to avoid making them reserved keywords - which would be somewhat > painful - is to add a 'DO' before the IGNORE/UPDATE. I.e. something like > > ON CONFLICT opt_conflict_expr DO OnConflictUpdateStmt > | ON CONFLICT opt_conflict_expr DO IGNORE > > Greetings, > > Andres Freund > > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers >
