Question

Is there any SQL subquery syntax that lets you define, literally, a temporary table?

For example, something like

SELECT
  MAX(count) AS max,
  COUNT(*) AS count
FROM
  (
    (1 AS id, 7 AS count),
    (2, 6),
    (3, 13),
    (4, 12),
    (5, 9)
  ) AS mytable
  INNER JOIN someothertable ON someothertable.id=mytable.id

This would save having to do two or three queries: creating temporary table, putting data in it, then using it in a join.

I am using MySQL but would be interested in other databases that could do something like that.

Answer 1

I suppose you could do a subquery with several SELECTs combined with UNIONs.

SELECT a, b, c, d
FROM (
    SELECT 1 AS a, 2 AS b, 3 AS c, 4 AS d
    UNION ALL 
    SELECT 5 , 6, 7, 8
) AS temp;