MySQL的3组通过与和

Question

我有我的表这个数据（tb_cash_transaction）

我想组类型列，CURRENCY_ID柱和金额列，因此这将成为象下面这样：

**Currency** **Cash IN** **Cash OUT** **Balance** 

14    40000  30000  10000   
15    50000  40000  10000 

规则：

1.Group通过货币
2.然后找到的现金总和为货币
3.Find的现金总和从该货币
4.Get余额（金额现金 - 现金和出）

如何使用MySQL来实现呢？我尝试使用group by，但无法获得所需的输出。

在此先感谢

Answer 1

SELECT currency_id, 
     SUM(CASE 
      WHEN TYPE = 'cash_in' THEN amount 
      END) AS cash_in, 
     SUM(CASE 
      WHEN TYPE = 'cash_out' THEN amount 
      END) AS cash_out, 
     SUM(CASE 
      WHEN TYPE = 'cash_in' THEN amount 
      ELSE -amount 
      END) AS balance 
FROM tb_cash_transaction 
WHERE TYPE IN ('cash_in', 'cash_out') /*<--- Where clause probably not needed 
             but just in case there are other options*/ 
GROUP BY currency_id 

Answer 2

试试这个：

SELECT a.currency_id, cash_in, cash_out, (cash_in - cash_out) balance 
    FROM (
       SELECT currency_id, SUM(AMOUNT) cash_in 
        FROM tb_cash_transaction 
       WHERE type = 'cash_in' 
       GROUP BY currency_id 
       ) a, 
       (
       SELECT currency_id, SUM(AMOUNT) cash_out 
        FROM tb_cash_transaction 
       WHERE type = 'cash_out' 
       GROUP BY currency_id 
       ) b 
    WHERE a.currency_id = b.currency_id 

Answer 3

select currency_id, cashin "Cash In", cashout "Cash Out", 
cashin-cashout "Balance" from (
    select currency_id, sum(if(type='cash_in',amount,0)) as cashin, 
    sum(if(type='cash_out',amount,0)) as cashout, 
    from tb_cash_transaction group by currency_id 
) 

Answer 4

这里是我使用的解决方案。感谢cybernate代码。

SELECT a.currency_id, cashin, cashout, (cashin - cashout) balance 
FROM (
      SELECT currency_id, SUM(AMOUNT) cashin 
      FROM tb_cash_transaction 
      WHERE type = 'cash_in' 
      GROUP BY currency_id 
      ) a, 
      (
      SELECT currency_id, SUM(AMOUNT) cashout 
      FROM tb_cash_transaction 
      WHERE type = 'cash_out' 
      GROUP BY currency_id 
      ) b 
WHERE a.currency_id = b.currency_id