SQLite

The SELECT statement below if valid syntax and ought to work, but SQLite rejects it and refuses to evaluate it:

CREATE TABLE x(a, b, PRIMARY KEY (a,b));
CREATE TABLE y(a);
CREATE TABLE z(a, b);
SELECT * FROM x JOIN y ON y.a = x.a  WHERE (x.a, x.b) IN (SELECT a, b FROM z);

This problem has been in the code since support for row-values was added with version 3.15.0 (2016-10-14). SQLite does not generate an incorrect answer because of this bug. Rather, SQLite merely refuses to process what ought to be valid SQL syntax.

Note that this problem was fixed prior to the ticket being created. The ticket was added after-the-fact for documentation purposes.

Forgot to say: The problem was reported on the sqlite-users mailing list by Mark Brand.