Select and summarize data from three tables - mysql

Question

i have three tables
customer
id | name
1 | john
orders
id | customer_id | date
1 | 1 | 2013-01-01
2 | 1 | 2013-02-01
3 | 2 | 2013-03-01
order_details
id | order_id | qty | cost
1 | 1 | 2 | 10
2 | 1 | 5 | 10
3 | 2 | 2 | 10
4 | 2 | 2 | 15
5 | 3 | 3 | 15
6 | 3 | 3 | 15
i need to select data so i can get the output for each order_id the summary of the order
sample output. I will query the database with a specific customer id
output
date | amount | qty | order_id
2013-01-01 | 70 | 7 | 1
2013-02-01 | 50 | 4 | 2
this is what i tried
SELECT
orders.id, orders.date,
SUM(order_details.qty * order_details.cost) AS amount,
SUM(order_details.qty) AS qty
FROM orders
LEFT OUTER JOIN order_details ON order_details.order_id=orders.id AND orders.customer_id = 1
GROUP BY orders.date
but this returns the same rows for all customers, only that the qty and cost dont hav values

Answer 1

Maybe
SELECT
orders.id, orders.date,
SUM(order_details.qty * order_details.cost) AS amount,
SUM(order_details.qty) AS qty
FROM orders
LEFT JOIN order_details ON order_details.order_id=orders.id
AND orders.customer_id = 1
GROUP BY orders.date
HAVING amount is not null AND qty is not null
SQL Fiddle

Answer 2

NOTE: In the following query, it is assumed that the dates are stored in the database as a string in the format specified in the OP. If they are actually stored as some type of date with time then you'll want to modify this query such that the time is truncated from the date so the date represents the whole day. You can use the date or date_format functions. But then you'll need to make sure that you modify the query appropriately so the group by and select clauses still work. I added this modification as comments inside the query.
select
o.date -- or date(o.date) as date
, sum(odtc.total_cost) as amount
, sum(odtc.qty) as qty
, o.order_id
from
orders o
inner join (
select
od.id
, od.order_id
, od.qty
, od.qty * od.cost as total_cost
from
order_details od
inner join orders _o on _o.id = od.order_id
where
_o.customer_id = :customer_id
group by
od.id
, od.order_id
, od.qty
, od.cost
) odtc on odtc.order_id = o.id
where
o.customer_id = :customer_id
group by
o.date -- or date(o.date)
, o.order_id
;

Answer 3

I don't think you want an outer join just a simple inner join on all 3 tables:
FROM orders, order_details, customer
WHERE orders.customer_id=customer.id
AND order_details.order_id=orders.id