How do you select every n-th row from mysql

Question

I have a series of values in a database that I need to pull to create a line chart. Because i dont require high resolution I would like to resample the data by selecting every 5th row from the database.

Answer 1

SELECT *  FROM (      SELECT          @row := @row +1 AS rownum, [column name]      FROM (          SELECT @row :=0) r, [table name]      ) ranked  WHERE rownum % [n] = 1  

Answer 2

You could try mod 5 to get rows where the ID is multiple of 5. (Assuming you have some sort of ID column that's sequential.)

select * from table where table.id mod 5 = 0;