Select Parent and Children With MySQL

Question

I know this question comes up often, but today I can\'t find the answer I\'m looking for. I have a table with this schema.

CREATE TABLE `comments` (
    `id`         


        

Answer 1

Parents are records with no parent_id.
Children have parent_id equal to the parent comment's id.

  SELECT ...
    FROM comments AS parent
         LEFT JOIN comments AS child 
         ON child.parent_id = parent.id
   WHERE parent.parent_id IS NULL
ORDER BY parent.id, child.id;

Note that the self-join should be an outer join so that you don't miss parent comments with no children.