如何匯總不同的值？

Question

+---+------------+
|sid| discounts  | 
+---+------------+
| 1 | 10.00      |
| 2 | 20.00      |
  2 | 20.00      |
+---+------------+

我需要獲取列折扣的總和，但是如果列sid具有相同的值，則只需將一行添加到總計中即可。

所以我要說30.00而不是50.00

我嘗試過這樣的事情

 SELECT DISTINCT sid FROM (SELECT SUM(discounts) FROM $table_name)

和

SELECT SUM(discounts) FROM $table_name WHERE sid IN (SELECT DISTINCT 'sid' FROM $table_name)

我只是收到“您的SQL語法有錯誤”

Answer 1

如果刪除single quuto betwwen sid第二個查詢將起作用

SELECT SUM(discounts) FROM $table_name WHERE sid IN (SELECT DISTINCT sid FROM $table_name)

Answer 2

select sum(discounts) from (select discounts,sid  from $table_name group by sid) t

Answer 3

我希望這會起作用

$sql=mysql_query("select SUM(discounts) from table_name groub by sid");

Answer 4

它很簡單，您可以使用

select SUM(discount) from (SELECT discount FROM  `table_name` group by sid) as discount

希望這對你有用

Answer 5

您可以嘗試使用以下SQL：

select 
    sum(t.discount) 
from 
    (select 
        distinct sid, discount 
    from 
        $table_name
    ) t

DEMO