
In the above table, c position is 3.
Is there any function to find the position in Mysql?

update

In the above table, c position is 3.
Is there any function to find the position in Mysql?

update
try
select @rownum:=@rownum+1 ‘theposition’, t.* from mytable t, (SELECT @rownum:=0) r order by t.USER desc;
Use this:
    SELECT x.user, 
       x.position,
       x.number
  FROM (SELECT t.user,
               t.number,
               @rownum := @rownum + 1 AS position
          FROM TABLE t
          JOIN (SELECT @rownum := 0) r
      ORDER BY t.number DESC) x
 WHERE x.user = 'c'
You can then get his position from x.position
I recommend you to add an id field. i don't know of any function to do that. you can select * and then in a script language search it or use a subquery. but i don't recommend that.
SELECT 
     @rowNumber := @rowNumber + 1 'RowNumber', 
     u.* 
FROM Users u, 
  (SELECT @rowNumber := 0) r
  ORDER BY u.User ASC