Generating Sequence for Each Group in MySQL -

how generate sequence mysql?
(n.b. :- each unique pair sequence generated afresh)

1,1 -- 1
1,1 -- 2
1,1 -- 3
1,2 -- 1
1,2 -- 2
1,3 -- 1
1,4 -- 1
1,4 -- 2
1,4 -- 3

you need row_number function in sql server mysql

select   @row_number := case     when @conc_no = conc     @row_number + 1     else     1     end num,   @conc_no := mydata.conc conc   (     select       concat(num1, ",", num2) conc           table1     order       num1 asc, num2 asc     ) mydata 

fiddle: http://sqlfiddle.com/#!9/ad4a0/3/0