这是我的查询
SELECT COUNT(*) as total, toys, date FROM T1
WHERE (date >= '2012-06-26'AND date < '2012-06-30') AND (Avail > '0')
UNION
SELECT COUNT(*) as total, toys, date FROM T2
WHERE (date >= '2012-06-26'AND date < '2012-06-30') AND (Avail > '0')
UNION
SELECT COUNT(*) as total, toys, date FROM T3
WHERE (date >= '2012-06-26'AND date < '2012-06-30') AND (Avail > '0')
GROUP BY RoomType
HAVING COUNT( total ) = 4
输出结果
count Toys date
3 Bibi 2012-06-26
4 Baba 2012-06-26
如何让 MYSQL 仅显示 count=4 的结果
SELECT * FROM (
SELECT COUNT(*) as total, toys, date FROM T1
WHERE (date >= '2012-06-26' AND date < '2012-06-30') AND (Avail > '0')
GROUP BY RoomType
UNION
SELECT COUNT(*) as total, toys, date FROM T2
WHERE (date >= '2012-06-26' AND date < '2012-06-30') AND (Avail > '0')
GROUP BY RoomType
UNION
SELECT COUNT(*) as total, toys, date FROM T3
WHERE (date >= '2012-06-26'AND date < '2012-06-30') AND (Avail > '0')
GROUP BY RoomType) AS src
WHERE total = 4;
请注意,为了正确进行数据分组,您必须将所有列放在 GROUP BY
子句中或作为聚合函数的参数。MySQL功能允许您避免此限制,但它可能会导致您获得意外结果。
您需要先分组,然后合并结果。
SELECT COUNT(*) as total, toys, date FROM T1
WHERE (date >= '2012-06-26'AND date < '2012-06-30') AND (Avail > '0')
GROUP BY RoomType HAVING COUNT( *) = 4
UNION
SELECT COUNT(*) as total, toys, date FROM T2
WHERE (date >= '2012-06-26'AND date < '2012-06-30') AND (Avail > '0')
GROUP BY RoomType HAVING COUNT( * ) = 4
UNION
SELECT COUNT(*) as total, toys, date FROM T3
WHERE (date >= '2012-06-26'AND date < '2012-06-30') AND (Avail > '0')
GROUP BY RoomType HAVING COUNT( * ) = 4