Question

I have this table called logs that logs a who input or output data.
Now I wan’t to get the statistics of who has the most contributions and rank them.

Columns are

 Occur_Time | iUser_id | iUsername | oUser_id | oUsername
 --iUser_id is the input persons index from another table that lists the username.
 --iUsername is the input persons name.
 --oUser_id is the index of the person who took the input away.
 --oUsername is the name of the person who took the input away.

Now I wan’t to know who has the most input.

My logic:

 Example:
     User_id is 1, name is One.
     Check how many times 1 is repeated on iUser_id = 100 times.
     Check how many times 1 is repeated on oUser_id = 10 times.
     User_id=1 has contributed 90 times.
     Then sort by who has most contribution.

Thank you.

Answer 1

(untested):

SELECT L.iUsername, 
((SELECT COUNT(1) FROM logs WHERE iUsername=L.iUsername) - 
(SELECT COUNT(1) FROM logs WHERE oUsername=L.iUsername)) as rank  
FROM logs L 
GROUP BY L.iUsername 
ORDER BY rank ASC