Sql sum() columns from different tables - php

Question

Category Table
mysql> SELECT * FROM cats;
+------+------+-----------+
| c_id | p_id | c_name |
+------+------+-----------+
| 1 | 1 | cats 1 |
| 2 | 1 | cats 2 |
| 3 | 1 | cats 3 |
+------+------+-----------+
Meta Table
mysql> SELECT * FROM meta;
+------+------+------+---------+-------------+-------+
| m_id | p_id | c_id | name | description | costs |
+------+------+------+---------+-------------+-------+
| 1 | 1 | 1 | Abhijit | description | 100 |
| 2 | 1 | 1 | Abhijit | description | 200 |
| 3 | 1 | 2 | Abhiji2 | description | 500 |
+------+------+------+---------+-------------+-------+
Transaction Table
mysql> SELECT * FROM transactions;
+------+------+------+---------------------+--------+
| t_id | p_id | m_id | date | amount |
+------+------+------+---------------------+--------+
| 1 | 1 | 1 | 2016-02-16 11:17:06 | 50 |
| 2 | 1 | 1 | 2016-02-16 11:17:06 | 50 |
| 3 | 1 | 2 | 2016-02-16 11:17:06 | 50 |
| 4 | 1 | 2 | 2016-02-16 11:17:06 | 150 |
+------+------+------+---------------------+--------+
I want to sum() for each category costs (from meta table) and amount( from transaction table).
I use:
mysql> SELECT c.*, SUM(t.amount), SUM(m.costs)
FROM cats c
LEFT JOIN meta m ON m.c_id=c.c_id
LEFT JOIN transactions t ON t.m_id=m.m_id
GROUP BY c.c_id;
+------+------+-----------+--------+---------------+--------------+
| c_id | p_id | c_name | add_by | SUM(t.amount) | SUM(m.costs) |
+------+------+-----------+--------+---------------+--------------+
| 1 | 1 | Abhijit | 1 | 100 | 400 |
| 2 | 1 | Abhiji2 | 1 | 200 | 500 |
+------+------+-----------+--------+---------------+--------------+
It's wrong. The Costs of cats id 1 is 300 but here I got 400
I Want Get Return From Query Like This:
+------+------+-----------+--------+---------------+--------------+
| c_id | p_id | c_name | add_by | SUM(t.amount) | SUM(m.costs) |
+------+------+-----------+--------+---------------+--------------+
| 1 | 1 | Abhijit | 1 | 100 | 300 |
| 2 | 1 | Abhiji2 | 1 | 200 | 500 |
+------+------+-----------+--------+---------------+--------------+

Answer 1

I think you had a typo (or error) in one of your JOIN conditions. I think you intended your original query to be this:
SELECT c.*, SUM(t.amount), SUM(m.costs)
FROM cats c
LEFT JOIN meta m ON m.c_id = c.c_id
LEFT JOIN transactions t ON t.m_id = m.c_id
GROUP BY c.c_id;
Note carefully ON t.m_id = m.c_id, which agrees with your expected output. In any case, I reworked your query as follows:
SELECT c.c_id, c.p_id, c.c_name, t2.transactionCosts, t1.metaCosts
FROM cats c
LEFT JOIN
(
SELECT c_id, SUM(costs) AS metaCosts
FROM meta
GROUP BY c_id
) t1
ON c.c_id = t1.c_id
LEFT JOIN
(
SELECT m_id, SUM(amount) AS transactionCosts
FROM transactions
GROUP BY m_id
) t2
ON c.c_id = t2.m_id
WHERE t2.transactionCosts IS NOT NULL OR t1.metaCosts IS NOT NULL;
The first subquery computes the meta total for each c_id, and the second subquery computes the transaction total for each m_id. These results are then both joined together with the cats table to get your final result.
Follow the link below for a running demo:
SQLFiddle

Answer 2

the problem is you select c.* but only group by c_id, in this case you have 2 options. window function or subquery.
via over(partition by):
SELECT c.*,
SUM(t.amount)over(partition by c.c_id) as amount,
SUM(m.costs)over(partition by c.c_id) as cost
FROM con_cats c
LEFT JOIN meta m ON m.c_id=c.c_id
LEFT JOIN transactions t ON t.m_id=m.m_id;
via subquery:
select a.*,b.amount,b.costs from con_cats a
inner join
(SELECT c.c_id, SUM(t.amount) as amount, SUM(m.costs) as costs
FROM con_cats c
LEFT JOIN meta m ON m.c_id=c.c_id
LEFT JOIN transactions t ON t.m_id=m.m_id
GROUP BY c.c_id) b
on a.c_id = b.c_id;