"David G. Johnston" <david.g.johns...@gmail.com> writes: > A correlated subquery, on the other hand, has to be called once for every > row and is evaluated within the context supplied by said row. Each time > random is called it returns a new value.
> Section 4.2.11 (9.6 docs) > https://www.postgresql.org/docs/9.6/static/sql-expressions.html#SQL-SYNTAX-SCALAR-SUBQUERIES > Maybe this could be worded better but the first part talks about a single > execution while "any one execution" is mentioned in reference to "the > surrounding query". > I do think that defining "correlated" and "non-correlated" subqueries > within this section would be worthwhile. Hmm ... a quick look around says we don't define or use those terms anywhere. I agree this could stand to be addressed somewhere, but I'm not sure if 4.2.11 is the most appropriate place. I don't think the issue is unique to scalar subqueries. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
