的MySQL和結果插入到表網格格式

Question

我有以下SQL代碼：

select distinct members_main.membership_type, 
payment_method,sum(amount_paid) 
from members_main, members_payments 
where members_main.contact_id=members_payments.contact_id 
group by members_main.membership_type,payment_method 

返回以下內容：

我希望能夠返回的結果以下表格格式：

有誰知道我是否可以在MySQL中做到這一點？

感謝，

約翰

Answer 1

根據數據的複雜性，可以採用bluefeet的方式，或者如果payment_method的數量是動態的，那麼它聽起來像需要一個數據透視表。嘗試看看this。

Answer 2

MySQL沒有一個支點功能，但你可以使用一個CASE表達和聚合函數打開行轉換成列：

select m.membership_type, 
    sum(case when p.payment_method = 'Cash' then amount_paid else 0 end) Cash, 
    sum(case when p.payment_method = 'Credit Card' then amount_paid else 0 end) CreditCard, 
    sum(case when p.payment_method = 'Paypal' then amount_paid else 0 end) Paypal 
from members_main m 
inner join members_payments p 
    on m.contact_id=p.contact_id 
group by m.membership_type; 

如果你將有一個未知數payment_method的，那麼你會想看看使用一個準備好的語句來生成動態SQL：

SET @sql = NULL; 
SELECT 
    GROUP_CONCAT(DISTINCT 
    CONCAT(
     'sum(CASE WHEN p.payment_method = ', 
     payment_method, 
     ' THEN amount_paid else 0 END) AS `', 
     payment_method, '`' 
    ) 
) INTO @sql 
FROM members_payments ; 

SET @sql 
    = CONCAT('SELECT m.membership_type, ', @sql, ' 
      from members_main m 
      inner join members_payments p 
       on m.contact_id=p.contact_id 
      group by m.membership_type'); 

PREPARE stmt FROM @sql; 
EXECUTE stmt; 
DEALLOCATE PREPARE stmt;