multilevel mysql query with a weird setup - mysql

Question

I have a problem. I am a codding newbie and learning php and mysql as i go.
i am working on an application and ran into a problem that i cant figure out.
I have three tables:
category:
+-----------+----------+--------------------+
| id | name | sort | active |
+-----------+----------+--------------------+
| 1 | apple | 1 | 1 |
| 2 | mango | 2 | 1 |
| 3 | blueberry| 3 | 0 |
+-----------+----------+--------------------+
service :
+-----------+----------+----------------------------------------+
| id | category_id | name | sort |active| process_time |
+-----------+------+------+--------+------+------+--------------+
| 1 | 1 | slices | 1 | 1 | 2 hours |
| 2 | 1 | half | 2 | 1 | 6 hours |
| 3 | 2 | slices | 1 | 1 | 1 hour |
| 4 | 2 | whole | 2 | 1 | 6 hours |
| 5 | 3 | bunch | 1 | 0 | 12 hours |
| 6 | 3 | a lot | 2 | 1 | 10 hours |
+-----------+------+---------+------+-------------+-------------+
user_price:
+-----------+----------+------+-------+---------+---------+---------+---------+
| id | user_id | 1 | 2 | 3 | 4 | 5 | 6 |
+-----------+----------+------+-------+---------+---------+---------+---------+
| 1 | 20 | 1 | 1 | 5 | 4 | 6 | 6 |
| 2 | 22 | 2 | 1 | 2 | 3 | 5 | 1 |
| 3 | 32 | 3 | 2 | 7 | 4 | 1 | 3 |
+-----------+----------+------+-------+---------+---------+---------+---------+
Categories have the categories that i sell in my store.
Services have the services that i offer in my store they correspond to the categories and are unique to only that category.
Prices have the user prices that i charge my customers every user has a different price the column names in the price table correspond to the services id.
Here is a SQLFiddle with sample data
Now here is the problem, in one sweep i would like to get a row that contains columns from all three tables for user_id 22 (user_id is only used for prices)
+---------------+----------------+-----------------+------------------+-----------+
| service_id | category_name | service_name | process_time | price |
+---------------+----------------+-----------------+------------------+-----------+
| 3 | mango | slices | 1 hour | 2 |
+---------------+----------------+-----------------+------------------+-----------+
Any ideas???

Answer 1

Try
SELECT s.id service_id,
c.name category_name,
s.name service_name,
s.process_time,
p.`3` price
FROM service s JOIN category c
ON s.category_id = c.id JOIN user_price p
ON p.user_id = 22
WHERE s.id = 3
Output:
| SERVICE_ID | CATEGORY_NAME | SERVICE_NAME | PROCESS_TIME | PRICE |
--------------------------------------------------------------------
| 3 | mango | slices | 1 hour | 2 |
Here is SQLFiddle demo
Now while it's not too late please normalize your user_price table. That will save you a lot of headache in the long run.
Your renewed schema for this table might look like
CREATE TABLE IF NOT EXISTS user_price
(
id int(11) NOT NULL AUTO_INCREMENT,
user_id int(11) NOT NULL,
service_id int(11) NOT NULL,
price decimal(19,2) DEFAULT '0.00',
PRIMARY KEY (id),
FOREIGN KEY (service_id) REFERENCES service (id),
UNIQUE KEY (user_id, service_id)
);
And the proper query using this table
SELECT s.id service_id,
c.name category_name,
s.name service_name,
s.process_time,
p.price
FROM service s JOIN category c
ON s.category_id = c.id JOIN user_price p
ON s.id = p.service_id
AND p.user_id = 22
WHERE s.id = 3
Here is a SQLFiddle demo. In this example the table has been named user_price1 to show you both queries side-by-side.