MySQL limit results per category

Question

Each item in c_data is in a category/section. I would like to limit how many items are displayed per category, rather than limiting the total number of items retrieved. Obvi

Answer 1

The answers to this previous post should help you to solve that problem.

EDIT:

It should work with using row numbers.

I have not tried it, but this should work:

set @section = '';
set @num  = 1;

SELECT y.*
FROM
(
    SELECT
      x.*, 
      @num := if(@section = sectionid, @num + 1, 1) as row_number,
      @section := sectionid
    FROM
    (
        SELECT 
          cm.id AS cm_id,
          cm.title AS cmtitle,
          cm.sectionid,
          cm.type AS cmtype,
          cd.id AS cd_id,
          cd.time,
          cd.link,
          cd.title,
          cd.description
        FROM c_main AS cm
        JOIN c_data AS cd ON ( cd.sectionid=cm.sectionid )
        ORDER by cd.sectionid ASC, cm.id ASC
    ) x
) y
WHERE y.row_number <= 20;