Display multiple results with INNER JOIN
I have these three MySQL tables:
companies services auxiliary id_company name_company id_service name_service id_company id_service 1 Google 1 Search 1 1 2 Yahoo 2 Calendar 1 2 3 Mail 1 3 4 Maps 1 4 2 1 2 3
I am wondering if I could display with only one query (I'm using php):
Google: Search, Calendar, Mail, Maps. Yahoo: Search, Mail.
Now what I am doing is display the companies, and for each company I make another MySQL query to display the services. Is it possible to do that with only one query? Thank you.
The answer to your question is: "Yes".
Oh, you want to know how to do it as well. The key is to join the tables together and then aggregate at the company level. I am going to assume that you really want the output as two columns (company name, services), rather than one string with them concatenated together.
The SQL is:
select c.name_company, group_concat(s.name_service separator ', ') as services from auxiliary a join companies c on a.id_company = c.id_company join services s on a.id_service = s.id_service group by c.id_company, c.name_company;
Yes, you could. Although in my opinion the approach you described seems more natural to me. (Having one query/cursor for the companies, and another one for the services)
You could use one single query to prepare following list: Google, Search Google, Calendar Google, Mail Google, Maps Yahoo, Search Yahoo, Mail ... (I have left out the ids for simplicity) Then you run through the list, every time the company changes you begin a new result line. I find this a bit more complicated than the approach you described.