This small query seems to segfault Postgres. I've tried on the
version of Postgres 11 that comes with Debian Stable and all versions
on https://www.db-fiddle.com/ including 13 (Beta). DB Fiddle actually
says "An unexpected error occurred." but I suspect that's the
segfault.
Tom
SELECT
0
FROM (SELECT
TRUE as "r",
SUM(0)
) as "T1",
LATERAL
(SELECT TRUE as "b"
UNION ALL
SELECT
"r" as "b"
FROM (SELECT 0 ORDER BY COALESCE(0)) as "T1"
) as "T2"
WHERE "b"