distinct records sum when joining different tables in mysql

Question

Table : O

ID  Date
1   2016-01-10
2   2016-01-10
3   2016-01-11

Table : OD

ODI   ID     Quantity
1     1        1 
2     1        2
3     2        1
4     3        1

Table: OH

OHI   ID
1     1         
2     2       
3     1        
4     3  

I have three table O,OD,OH. I need to join these three table and get the sum of quantity For each day.
Tried

SELECT O.date,SUM(od.Quantity),group_concat(OHI) FROM O
INNER JOIN OD ON OD.ID = O.ID
INNER JOIN OH ON OH.ID = O.ID
GROUP BY O.date;

But the resulting quantity sum was different due to joining the OH Table.Now How do i get the proper Sum.

Expected Result :

Date   SUM(od.Quantity)
2016-01-10        4       
2016-01-10        1

Sorry For Change In The Question.

Answer 1

You don't need to join OH table, this can be done with below query:

SELECT O.ID,SUM(od.Quantity) FROM O
INNER JOIN OD ON OD.ID = O.ID
GROUP BY O.ID;

Answer 2

You don't need to join with the OH table.

select O.ID, SUM(OD.Quantity) total_qty
from O inner join OD
on O.ID = OD.ID
group by O.ID;

If you need join with OH, then do it after aggregation.

select *
from OH inner join (
    select O.ID, SUM(OD.Quantity) total_qty
    from O inner join OD
    on O.ID = OD.ID
    group by O.ID
) t on t.ID = OH.ID;

Answer 3

Aggregate over the OD table first in a subquery, then join this to the other two tables:

SELECT t1.Date,
       t2.Quantity,
       t3.OHI   -- and possibly other columns from OH
FROM O t1
INNER JOIN
(
    SELECT ID, SUM(Quantity) AS Quantity
    FROM OD
    GROUP BY ID
) t2
    ON t1.ID = t2.ID
INNER JOIN OH t3
    ON t1.ID = t3.ID