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Help with an interesting Postgres question: Why isn't an Index Only Scan used on a partition accessed via the parent table?.
WITH emp (id, fname, name) AS (
VALUES (1, 'A', 'A'),
(2, 'C', 'A'),
(3, 'B', 'B')
)
SELECT DISTINCT name
FROM emp
ORDER BY fname DESC
ERROR: for SELECT DISTINCT, ORDER BY expressions must appear in select list
LINE 8: ORDER BY fname DESC
^