獲取mysql中所有值的總和

Question

假設我有下表。

mysql> desc items; 
+---------------+------------------------+------+-----+---------+-------+ 
| Field   | Type     | Null | Key | Default | Extra | 
+---------------+------------------------+------+-----+---------+-------+ 
| item_value | int(11)    | YES |  | NULL |  | 
| item_quantity | smallint(5)   | YES |  | NULL |  | 
+---------------+------------------------+------+-----+---------+-------+ 

當前的SQL語句是簡單的用1

select sum(item_value) as total_value from items where user_id = ? 

量的項目如果某行已超過1個數量，我想考慮到這一點時，我加起來值爲所有用戶。跟蹤每行總數（item_quantity * item_value）還是可以在SQL語句中執行？

Answer 1

你可以做算術的sum()聲明：

select sum(item_quantity * item_value) as total_value from items where user_id = ?