[英]calculate the count and then sum of total count MySql
我的查询
$sql = 'SELECT status FROM tablename';
结果
------------
status
------------
assigned
assigned
assigned
assigned
assigned
accepted
accepted
completed
completed
completed
completed
completed
现在我可以找到每个状态的总数
SELECT status, COUNT(status) AS cnt
FROM tname
GROUP BY b.statusName
HAVING (cnt >= 1)
这将给
status cnt
--------------
accepted 2
assigned 5
completed 5
我如何只completed
和已accepted
计数?
将条件放在sum()函数中时,这称为条件求和:
SELECT SUM(IF(status IN ('accepted','assigned'),cnt,0)) as sum_of_acc_asg
FROM
(SELECT status, COUNT(status) AS cnt
FROM tname
GROUP BY b.statusName
HAVING (cnt > 1)) t
或者,您可以使用where首先过滤子查询:
SELECT SUM(cnt) as sum_of_acc_asg
FROM
(SELECT status, COUNT(status) AS cnt
FROM tname
WHERE status IN ('accepted','assigned')
GROUP BY b.statusName
HAVING (cnt > 1)) t
其操作简单,取代group by
由where
SELECT status, COUNT(status) AS cnt
FROM tname
WHERE b.statusName IN ('completed','accepted')
HAVING (cnt > 1)
从tname中选择COUNT(状态)AS cnt status =“已完成”或status =“已接受”
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