Retrieve values from multiple tables relationed - php

Question

So, I have a table named clients, another one known as orders and other two, orders_type_a and orders_type_b.
What I'm trying to do is create a query that returns the list of all clients, and for each client it must return the number of orders based on this client's id and the amount of money this customer already spent.
And... I have no idea how to do that. I know the logic behind this, but can't find out how to translate it into a MySQL query.
I have a basic-to-thinkimgoodbutimnot knowledge of MySQL, but to this situation I've got really confused.
Here is a image to illustrate better the process I'm trying to do:
Useful extra information:
Each orders row have only one type (which is A or B)
Each orders row can have multiple orders_type_X (where X is A or B)
orders relate with client through the column client_id
orders_type_X relate with orders through the column order_id
This process is being made today by doing a query to retrieve clients, and then from each entry returned the code do another query (with php) to retrieve the orders and yet another one to retrieve the values. So basically for each row returned from the first query there is two others inside it. Needless to say that this is a horrible approach, the performance sucks and I thats the reason why I want to change it.
UPDATE width tables columns:
clients:
id | name | phone
orders:
id | client_id | date
orders_type_a:
id | order_id | number_of_items | price_of_single_item
orders_type_b:
id | order_id | number_of_shoes_11 | number_of_shoes_12 | number_of_shoes_13 | price_of_single_shoe
For any extra info needed, just ask.

Answer 1

If I understand you correctly, you are looking for something like this?
select c.*, SUM(oa.value) + SUM(ob.value) as total
from clients c
inner join orders o on c.order_id = o.id
inner join orders_type_a oa on oa.id = o.order_type_id AND o.type = 'A'
inner join orders_type_b ob on ob.id = o.order_type_id AND o.type = 'B'
group by c.id
I do not know your actual field names, but this returns the information on each customer plus a single field 'total' that contains the sum of the values of all the orders of both type A and type B. You might have to tweak the various names to get it to work, but does this get you in the right direction?

Answer 2

Erik's answer is on the right track. However, since there could be multiple orders_type_a and orders_type_b records for each order, it is a little more complex:
SELECT c.id, c.name, c.phone, SUM(x.total) as total
FROM clients c
INNER JOIN orders o
ON o.client_id = c.id
INNER JOIN (
SELECT order_id, SUM(number_of_items * price_of_single_item) as total
FROM orders_type_a
UNION ALL
SELECT order_id, SUM((number_of_shoes_11 + number_of_shoes_12 + number_of_shoes_13) * price_of_single_shoe) as total
FROM orders_type_b
) x
ON x.order_id = o.id
GROUP BY c.id
;
I'm making a few assumptions about how to calculate the total based on the columns in the orders_type_x tables.