select every other row in MySQL without depending on any ID?

Question

Considering following table that doesn\'t have any primary key, can I select every other row?

col1      col2
 2         a
 1         b
 3         c
 12               


        

Answer 1

In unique MySQL fashion:

select  *
from    (
        select  *
        ,       @rn := @rn + 1 as rn
        from    Table1
        join    (select @rn := 0) i
        ) s
where   rn mod 2 = 0 -- Use = 1 for the other set

Example at SQL Fiddle.