Question

I have a database of users where they can send messages to other users (up to four) and the ID of the message they sent is in their user row.

Name    | Email       | Msg1 | Msg2 | Msg3 | Msg4
--------+-------------+------+------+------+-----
Pez     | [e-mail]   |  1   |  55  |  42  |  5 
Steve   | [e-mail] |  0   |   0  |   0  |  0 
Leon    | [e-mail] |  3   |   0  |   3  |  5 

How in a MySQL query can I get the amount of those message rows that are not empty or not equal to 0, allowing me to order by that? So it would return

Pez   | 4 Mesasges
Leon  | 3 Messages
Steve | 0 Messages

Im my mind something like:

order by count(!empty(msg1)+!empty(msg2)+!empty(msg3)+!empty(msg4)) 

Answer 1

With normalized tables it could be as simple as

SELECT Count(*) FROM messages WHERE userid=47

But with your schema try something like

SELECT
  name,
  (msg1<>0) + (msg2<>0) + (msg3<>0) + (msg4<>0) as cMessages
FROM
  foo  

edit: Vincent Ramdhanie’s answer using if() doesn’t rely on MySQL’s behaviour to use 0 as false and 1 as true as result of a comparison. I would prefer that.