mySQL - 列的总和

Question

我有两张 table

表 1

id product
1  P1
2  P2

表2

id amount product_t1
1  100    P1
2  200    P1
3  300    P2
4  400    P1
5  500    P2

我希望我的输出是:

product totalAmount(sum of amount)
P1      700
P2      800

编辑:这是我到目前为止的查询

SELECT T1.product, SUM(T2.amount)
FROM table1 T1
INNER JOIN table2 T2
ON T1.product = T2.product_t1

谢谢!

Answer 1

你应该使用分组方式

 SELECT T1.product, SUM(T2.amount)
 FROM table1 T1
 INNER JOIN table2 T2
 ON T1.product = T2.product_t1
 GROUP BY product