How to SUM column in MySQL left join - mysql

Question

So i have table cont_selling
---------------------------------
cont_selling_id | date |
---------------------------------
1 | 2015-05-24 |
2 | 2015-06-06 |
---------------------------------
table 02 cont_sold
----------------------------------------------------
cont_sold_id | cont_selling_id | price |
---------------------------------------------------
1 | 1 | 10 |
2 | 1 | 10 |
3 | 1 | 30 |
4 | 2 | 20 |
5 | 2 | 10 |
--------------------------------------------------
and table 03 payment
----------------------------------------------
payment_id | cont_selling_id | paid |
-----------------------------------------------
1 | 1 | 10 |
2 | 2 | 10 |
3 | 1 | 20 |
4 | 1 | 10 |
5 | 2 | 10 |
-----------------------------------------------
now i need to SELECT table based on
now i want to merge all these three tables based on cont_selling table cont_selling_id column
and want to SUM cont_sold table price column and payment table paid column
this is what i want to do
expecting output
---------------------------------------------
cont_selling_id | price | paid |
---------------------------------------------
1 | 50 | 40 |
2 | 30 | 20 |
---------------------------------------------
so i tried like this in mysql query but it give wrong sum result
SELECT
SUM(Z.price) as total,
SUM(P.amount) as paid
FROM cont_selling S
LEFT JOIN cont_sold Z
ON S.cont_selling_id = Z.cont_selling_id
LEFT JOIN payment P
ON S.cont_selling_id = P.cont_selling_id
GROUP BY S.cont_selling_id
for this above query i m getting output like this
---------------------------------------------
cont_selling_id | price | paid |
---------------------------------------------
1 | 150 | 40 |
2 | 60 | 120 |
---------------------------------------------

Answer 1

Here how you can do it using the aggegare part into inner queries and then join
select
cs.cont_selling_id,
price,
paid
from cont_selling cs
left join(
select sum(price) as price , cont_selling_id from cont_sold
group by cont_selling_id
)x on x.cont_selling_id = cs.cont_selling_id,
left join(
select sum(paid) as paid , cont_selling_id from payment
group by cont_selling_id
)y
on y.cont_selling_id = cs.cont_selling_id;

Answer 2

You should make two different queries with SUM and then combine them to get the desired result:
SELECT T1.cont_selling_id,T1.price,T2.paid
FROM
(SELECT c.cont_selling_id,SUM(cs.price) as price
FROM cont_selling c LEFT JOIN
cont_sold cs ON c.cont_selling_id=cs.cont_selling_id
GROUP BY c.cont_selling_id) as T1 JOIN
(SELECT c.cont_selling_id,SUM(p.paid) as paid
FROM cont_selling c LEFT JOIN
payment p ON p.cont_selling_id=c.cont_selling_id
GROUP BY c.cont_selling_id) as T2 ON T1.cont_selling_id=T2.cont_selling_id
Result:
cont_selling_id price paid
----------------------------
1 50 40
2 30 20
Sample result in SQL Fiddle.

Answer 3

This untested query should work:
with a as(select cont_selling_id , sum(price) as totalprice from cont_sold group by cont_selling_id),
with a as(select cont_selling_id , sum(paid) as totalpaid from payment group by cont_selling_id),
select c.cont_selling_id , totalprice, totalpaid from cont_selling c left join a.count_selling_id = c.count_selling_id
left join b.count_selling_id = c.count_selling_id
You have to create temporary tables, because there is no dependency between your table for price and paid.