mysql-從帶有sum（）和where子句的表中選擇

Question

這是我的桌子

|id | code | amount |
----------------------
|1  |  01  | 500    | 
|2  |  02  | 2500   | 
|3  |  03  | 700    | 
|4  |  04  | 500    | 
|5  |  05  | 500    | 
|6  |  06  | 500    | 

我想顯示以（01,03,05）中的代碼作為借方和（02,04,06）作為貸方的行的總和結果，因此結果看起來像這樣

|id | code | debit  | credit |
------------------------------
|   |      | 1700   | 3500   |

怎么辦呢？ 提前致謝 ：）

Answer 1

一種選擇是使用conditional aggregation ：

select 
    sum(case when code in ('01','03','05') then amount end) debit,
    sum(case when code in ('02','04','06') then amount end) credit
from yourtable

Answer 2

另一種變體，有時既沒有條件聚合也可能更好：

select sum(debit), sum(credit) from
(
select sum(amount) as debit, 0 as credit
from table where code in ('01','03','05')
union all
select 0, sum(amount)
from table where code in ('02','04','06')
) as q

實際性能取決於表的結構/大小/索引，因此請運行explain以找出更合適的變體