計算計數，然後總計數的總和MySql的

Question

我的查詢

$sql = 'SELECT status FROM tablename'; 

而結果

------------ 
status 
------------ 
assigned 
assigned 
assigned 
assigned 
assigned 
accepted 
accepted 
completed 
completed 
completed 
completed 
completed 

現在，我能找到的每一個狀態

SELECT status, COUNT(status) AS cnt 
FROM tname 
GROUP BY b.statusName 
HAVING (cnt >= 1) 

這總計數將給

---

status  cnt 
-------------- 
accepted 2 
assigned 5 
completed 5 

我如何求和只有completed和accepted算？

Answer 1

這就是所謂的條件求和，更換group by當你用sum（）函數中的條件：

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 

或者你可以用在哪裏篩選子查詢第一：

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 

Answer 2

其簡單，通過where

SELECT status, COUNT(status) AS cnt 
FROM tname 
WHERE b.statusName IN ('completed','accepted') 
HAVING (cnt > 1) 

Answer 3

SELECT COUNT（狀態） AS cnt FROM tname WHERE status ='completed'or status ='accepted'