如何排除Mysql组
我想知道如何排除mysql组,我在这里做了一段时间的研究,但就是做不好 我试过了如何排除Mysql组,mysql,Mysql,我想知道如何排除mysql组,我在这里做了一段时间的研究,但就是做不好 我试过了 SELECT * FROM booking GROUP BY BookingId HAVING Status!="Cancellation" 这显然不起作用 示例数据库如下所示: +----+-----------+--------------+ | id | BookingId | Status | +----+-----------+--------------+ | 1 | 1
SELECT * FROM booking GROUP BY BookingId HAVING Status!="Cancellation"
这显然不起作用
示例数据库如下所示:
+----+-----------+--------------+
| id | BookingId | Status |
+----+-----------+--------------+
| 1 | 1 | Booked |
| 2 | 1 | Cancellation |
| 3 | 2 | Booked |
+----+-----------+--------------+
我想按BookingId对它们进行分组,如果找到的条目之一获得状态取消,则该组不应显示,因此从上面只会看到id 3。您需要在having子句中使用聚合函数,如
sum
SELECT BookingId
FROM booking
GROUP BY BookingId
HAVING sum(Status = 'Cancellation') = 0