Question

我有一个交易表，想要根据交易类型进行计算。怎么样？

表：

id | amount | type
--------------------
01 | 230    | IncomingTransfer
02 | 100    | OutcomingTransfer
03 | 20     | IncomingTransfer

逻辑：

SELECT SUM(amount)
IF IncomingTransfer
    + 230
    + 20
ELSE IF OutcomingTransfer
    - 100

Total amount: +150

Answer 1

就像我的 sqlfiddle 一样简单：

Answer 2

SELECT SUM(amount) FROM (
   SELECT CASE WHEN type='IncomingTransfer'
      THEN +amount
      ELSE -amount
      END as amount
   FROM MyTable
) as data

Answer 3

我会用：

    SELECT Amount = SUM(CASE WHEN Type = 'OutcomingTransfer' then (Amount*-1) 
                    ELSE Amount END)
    FROM <Table>
    GROUP BY <Grouping Field>

如何使用条件的SQL SUM

3 个答案: