Postgres 11

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

Help with an interesting Postgres question: Why isn't an Index Only Scan used on a partition accessed via the parent table?.

select version();

version

PostgreSQL 11.2 (Debian 11.2-1.pgdg90+1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 6.3.0-18+deb9u1) 6.3.0 20170516, 64-bit

CREATE TABLE tt (c int) ; 
INSERT INTO tt (c) VALUES (1) ;
1 rows affected

SELECT c cost 
FRO  tt;
ERROR:  syntax error at or near "cost"
LINE 1: SELECT c cost 
                 ^

SELECT c AS cost 
FROM tt;

cost

1

SELECT c "cost"
FROM tt;

cost

1