Show two or more rows in a single row - php

Question

I have these four tables:
table offers
id
id_company
description
table companies
id
name
table company_customer
id_company
id_customer
table customers
id
name
I need to get the offers, the company that has the offer and also the customers which have a relation with those companies. It's quite simple.
The query I'm typing is the following:
SELECT c.name, c.description, cu.name cu_name
FROM companies c
INNER JOIN offers o ON o.id_company = c.id
INNER JOIN company_customer cc ON cc.id_company = c.id
INNER JOIN customers cu ON cu.id = cc.id_customer
WHERE o.id_company = 1
ORDER BY o.id_company;
The "problem" is that sometimes an offer of a company is available for diferent customers.
Let me to show you the problem with a real example:
'Ebay' | 'offer number 1' | 'customer 1'
'Ebay' | 'offer number 1' | 'customer 2'
But I need concatenate or show both rows on a single row (just in the cases that company and the offer is the same but the customers are different). In other words, I need the following result:
'Ebay' | 'offer number 1' | 'customer 1, customer 2'
I work with PHP and MySQL. I know this may be done with PHP but I'm wondering if it could be possible to do it just with MySQL.
Any ideas??
Any help would be really appreciated. My apologize for my english level. I know it's not my best.
Thanks in advance for your time and attention.

Answer 1

You need to group by both company and offer, so you want this query:
SELECT
c.`name` AS companyName,
o.description AS offerName,
GROUP_CONCAT(cs.`name` ORDER BY cs.id) AS customerNames
FROM
companies c
INNER JOIN offers o ON o.id_company = c.id
INNER JOIN company_customer cc ON cc.id_company = c.id
INNER JOIN customers cs ON cs.id = cc.id_customer
WHERE
c.id = 1
GROUP BY
c.`name`,
o.description
Amyway there is no relation between offers and customers in your database, so you might consider to add such. Otherwhise all company's customers will appear in each offer of this company:
+-------------+-----------+----------------------------------+
| companyName | offerName | customerNames |
+-------------+-----------+----------------------------------+
| Ebay | Offer 1 | Customer 1,Customer 2,Customer 3 |
| Ebay | Offer 2 | Customer 1,Customer 2,Customer 3 |
+-------------+-----------+----------------------------------+
2 rows in set
But if you want exacly that, everything is OK then.

Answer 2

You can use a the aggregated GROUP_CONCAT Function
SELECT c.name, c.description, GROUP_CONCAT(string SEPARATOR ',')
FROM <<table And Joins...>>
GROUP BY c.name, c.description;
See hier http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat

Answer 3

There is no way to represent this in your current table design, because an offer can reference (at most) one company. To do what you wish, you will need to add an offer_company table with id_company and id_offer, and remove the id_company field from the offer table. Then you will add an additional join column to your query, and a group by clause to group the rows with the same offer together.
Once you have the rows grouped together, you can merge them into a single row, concatenating the customer information, in your php code.