经过大量研究,我想出了解决我问题的方法。实际上,我在使用带有条件子句的错误方式使用where条件。
SELECT u_exchange_id FROM games_exchange
WHERE
u_exchange_id IN
( SELECT u_exchange_id FROM games_exchange WHERE game_id = 7 AND
exchange_type = 1 )
AND
u_exchange_id IN
( SELECT u_exchange_id FROM games_exchange WHERE game_id = 7 AND
exchange_type = 2)
GROUP BY u_exchange_id
HAVING COUNT( u_exchange_id ) = 2