Limiting query to certain amount of rows evenly distributed
You have a dynamic number of rows in the table, and want a specific number of evenly distributed results each time?

I'm asking because the solution you linked is already nearly there: 

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


Just replace [n] with the following:

(CEIL(@row/[m]))


where [m] is the number of results you want to have returned.