Question

I have these tables:

comments

uid
id
pid

pages

pid
user

users

id
rank
.
.
.

and this query:

SELECT
   u.*, 
   count(p.id) as 'pages',
   count(c.id) as 'comments' 
FROM 
  `users` u 
   LEFT OUTER JOIN `pages` p ON p.user = u.id
   LEFT OUTER JOIN `comments` c ON c.uid = u.id
GROUP BY u.id

For some reason it shows 2 comments for a user when he has only 1.

Is there a problem in the query?

Answer 1

The problem is that the user is multiplied by his number of pages, and then by his number of comments. One way to fix that is count(distinct ..):

count(distinct p.id) as 'pages',
count(distinct c.id) as 'comments'