I was playing with mysql client,suddenly found that it would be really great if I can rank the query results.Lets say we have a table like below:

Now we want to rank  the students based on their Roll No.To do it,we have to define a variable with the initial value of 0 and in next query we will show it by as one of the resulted field  query

like below:

set @counter=0;

select @counter:=@counter+1 as Rank,LastName,Roll_no as Roll  from Students order by Roll_no ASC;

and in next query we will show it by as one of the resulted field ,that results:

Check mysql docs from here to know details about user defined variable in mysql