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

This should work for MySQL:

SELECT col1, col2
FROM (
   SELECT col1, col2, @rowNumber:=@rowNumber+ 1 rn
   FROM YourTable
      JOIN (SELECT @rowNumber:= 0) r
) t 
WHERE rn % 2 = 1

This uses % which is the MOD operator.

And here is the sample fiddle: http://sqlfiddle.com/#!2/cd31b/2