On 2020-Apr-08, Andrew Gierth wrote: > >>>>> "Alvaro" == Alvaro Herrera <alvhe...@2ndquadrant.com> writes: > > Alvaro> It turns out that the SQL standard is much more limited in what > Alvaro> it will accept there. But our grammar (what we'll accept for > Alvaro> the ancient LIMIT clause) is very lenient -- it'll take just > Alvaro> any expression. I thought about reducing that to NumericOnly > Alvaro> for FETCH FIRST .. WITH TIES, but then I have to pick: 1) > Alvaro> gram.y fails to compile because of a reduce/reduce conflict, or > Alvaro> 2) also restricting FETCH FIRST .. ONLY to NumericOnly. Neither > Alvaro> of those seemed very palatable. > > FETCH FIRST ... ONLY was made _too_ restrictive initially, such that it > didn't allow parameters (which are allowed by the spec); see 1da162e1f.
Hmm, oh, I see. > (That change didn't present a problem for ruleutils, because FETCH FIRST > ... ONLY is output as a LIMIT clause instead.) Right, I noticed that and kept it unchanged. > This needs to be fixed in ruleutils, IMO, not by changing what the > grammar accepts. Fair. I didn't change what the grammar accepts. I ended up only throwing an error in parse analysis when a bare NULL const is seen. I guess we could fix ruleutils to add parens when NULL is seen, but I'm not sure it's necessary or useful. (LIMIT uses a null to represent the LIMIT ALL case.) -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
