sql查询到相同id但不同值的总和？

Question

sql query to sum of same id but different value??.... I am trying to calculate sum of same id...following is my table

id        barter_value
2           50,000
2           1,50,000
3           47,000
3           55,000
3           50,00,000

I want output like

id       barter_value
2          2,00,000
3          51,00,2000


select a.buyer_id, 
       a.prod_barter_val 
       from add_to_cart as a
       join(select buyer_id, 
            sum(prod_barter_val) as total 
            from add_to_cart group by buyer_id) as b 
            on a.buyer_id = b.buyer_id;

Answer 1

你可以这样做：

select buyer_id, sum(prod_barter_val) from add_to_cart group by buyer_id

Answer 2

You're almost there, just change the sql statment ( b.total ):

select buyer_id, 
   sum(prod_barter_val) as total 
   from add_to_cart
   group by buyer_id

Answer 3

SELECT id, SUM(barter_value) as 'total' FROM table GROUP BY id

What this does: Selects all the ID's and the barter values from the table. Then the GROUP BY takes effect, and all ID's that are equal are joined into one row.

Without the SUM you would end up with just a random value in the barter_value column, but with SUM it adds all the rows together for the ID's (seperately) and puts that in the total column.