how to sum column values with same id [closed]

Question

with this query :

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SELECT a.nid, a.stock, b.qty
FROM uc_product_stock a
INNER JOIN uc_order_products b ON a.nid = b.nid

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I have the following result:

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nid stock   qty
11  256     4
11  256     1
11  256     4
11  256     1
11  256     1
10  746     1
10  746     2
10  746     1

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now i want to sum qty column with same id 11 and 10 i.e my result should be

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 nid    stock   qty
 11     256     11
 10     746     4

Answer 1

You just need to group by the relevant columns, and use an aggregate functin (SUM in this case):

SELECT 
a.nid, a.stock, sum(b.qty)
FROM 
uc_product_stock a INNER JOIN uc_order_products b ON a.nid = b.nid
group by 
a.nid, a.stock