SELECT LEVEL,man,woman FROM(
SELECT LEVEL,COUNT(*) AS 'woman' FROM
(SELECT id,LEVEL,sex FROM player_attributes WHERE sex=1)t1 GROUP BY LEVEL
UNION ALL
SELECT LEVEL,COUNT(*) AS 'man' FROM
(SELECT id,LEVEL,sex FROM player_attributes WHERE sex=0)t2 GROUP BY LEVEL
)t5 GROUP BY LEVEL
运行后报错：Unknown column 'man' in 'field list'
