Question

I have table users and another table premium_users in which I hold the userid and the date when he bought premium membership.

How can I use mysql join , so that in a single query I can select all the columns from the table users and also know for each premium user the date he joined on.

USERS:

ID USERNAME
1  JOHN
2  BILL
3  JOE
4  KENNY

PREMIUM USERS:

ID USERID DATE
1  2      20/05/2010
2  4      21/06/2011

And the final table (the one that will be returned my the query) should look like this:

ID USERNAME DATE
1  JOHN
2  BILL     20/05/2010
3  JOE
4  KENNY    21/06/2011

Is it ok for some rows to have the DATE value empty?
How can I check if that value is empty? $row['date']=='' ?

EDIT:
This was only an example, but the users table has much more columns, how can I select all from users and only date from premium_users without writing all the columns?

Answer 1

select u.*, pu.DATE
from USERS u LEFT OUTER JOIN PREMIUM_USERS pu on
  u.ID = pu.USERID

You can check if a row is empty with:

if (!$row['DATE'])
{
   ... 
}