Question

下面的MySQL查詢的次數會給出一個結果如下

$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" 

結果

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  

在這裏，我想每個program_id

的count對於例如：count（172），count（173）等。

id count 
172 2 

Answer 1

你可以用你的查詢在subqery在這樣的外部查詢計數：

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：在你發佈你被PS.programs_subscribed_id分組和選擇PS.user_id, PS.pro_id查詢SELECT子句既不在聚合函數中，也不在GROUP BY子句中，因此您不會以這種方式獲得不一致的數據。

你可以這樣做，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; 

這樣，多餘的JOIN與子查詢：

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

將確保從pro_Purchase表中選擇每一行都有COUNT(pro_id) > 1每個programs_subscribed_id和這就是爲什麼你在第一個查詢中按programs_subscribed_id進行分組的原因。