Question

下面的MySQL查询的次数会给出一个结果如下

$query = "SELECT PS.user_id, PS.pro_id 
    FROM pro_Purchase AS PS 
    INNER JOIN program_detail AS PD ON PD.program_master_id = PS.pro_id 
    WHERE PD.program_type = 'program' 
    AND PS.subscribe_status = '1' 
    GROUP BY PS.`programs_subscribed_id` 
    HAVING COUNT(`pro_id`) > '1' 
    ORDER BY PS.pro_id" 

结果

user_id program_id 
97  167  
12  172  
12  172  
216  173  
216  173  
215  173  
216  173  
12  173  
12  173  
12  173  
216  173  

在这里，我想每个program_id

的count对于例如：count（172），count（173）等。

id count 
172 2 

Answer 1

你可以用你的查询在subqery在这样的外部查询计数：

SELECT 
    user_id, COUNT(pro_id) 
FROM 
(
    SELECT PS.user_id, PS.pro_id 
    FROM pro_Purchase AS PS 
    INNER JOIN program_detail AS PD ON PD.program_master_id = PS.pro_id 
    WHERE PD.program_type = 'program' 
     AND PS.subscribe_status = '1' 
    GROUP BY PS.programs_subscribed_id 
    HAVING COUNT(pro_id) > '1' 
) AS Sub 
GROUP BY user_id 
ORDER BY pro_id; 

需要注意的是：在你发布你被PS.programs_subscribed_id分组和选择PS.user_id, PS.pro_id查询SELECT子句既不在聚合函数中，也不在GROUP BY子句中，因此您不会以这种方式获得不一致的数据。

你可以这样做，而不是：

SELECT PS.pro_id, COUNT(PS.user_id) 
FROM pro_Purchase AS PS 
INNER JOIN 
(
    SELECT programs_subscribed_id 
    FROM pro_Purchase 
    GROUP BY programs_subscribed_id 
    HAVING COUNT(pro_id) > 1 
) AS PS2 ON PS.programs_subscribed_id = PS2.programs_subscribed_id 
INNER JOIN program_detail AS PD ON PD.program_master_id = PS.pro_id 
WHERE PD.program_type = 'program' 
    AND PS.subscribe_status = '1' 
GROUP BY PS.pro_id; 

这样，多余的JOIN与子查询：

SELECT programs_subscribed_id 
    FROM pro_Purchase 
    GROUP BY programs_subscribed_id 
    HAVING COUNT(pro_id) > 1 

将确保从pro_Purchase表中选择每一行都有COUNT(pro_id) > 1每个programs_subscribed_id和这就是为什么你在第一个查询中按programs_subscribed_id进行分组的原因。