How to declare and use mysql variable to get expected result

See more:

PHP

MySQL

Hi All,

I am finding problem in get correct result from query that I have written.
Below is my mysql query to get the levelId,levelRange,16,NextRange from database

"select levelId,levelRange,16 as totalSave,
(		
  case @i:=(level+1) 
	when @i then (select levelRange from level where levelId=@i;)					
  End
) As  NextRange
from level where levelRange <= 16 order by levelId desc limit 1"

I have used this query in PHP.
But it always gives me result as 0,0,16,NULL respectively for respective select items.

database table "level" is as follow,

levelId| levelRange
   1   |    5
   2   |    10
   3   |    15
   4   |    20
   5   |    25

Here, the value "16" decides the next range value. So expected result should be "3,15,16,20"
where "levelId=3,levelRange=15,totalSave=16,NextRange=20".

Is their any way to get this result. I am using @i as to make it dynamic. So that no change will be required from coding side if in future levelId and levelRange changes from database