On Tue, Nov 22, 2022 at 2:11 PM Eagna <ea...@protonmail.com> wrote: > > NUMBER 2 > > > SELECT ROW(1, 2.5, 'this is a test') = (VALUES (1, 2.5, 'this is a > test')) AS test2; > > My question is that if a ROW constructor works for a VALUES clause in > statement NUMBER 2, then why not NUMBER 3? >
You've drawn a false equivalence from the similarity of the syntax. The following also works: SELECT 1 = (SELECT 1*1); But I don't think there is any argument that while this works: INSERT INTO tbl (col) SELECT 1*1; This doesn't: INSERT INTO tbl (col) 1; There is no difference with replacing 1 with a composite type and the SELECT subquery with VALUES instead. Your "VALUES" is just a scalar subquery expression that, if it indeed produces a single row and column, can be compared to any other scalar value (if it produces more than one row you will get an error - try it). David J.
