Cascading JOINs

Show parents, children and grandchildren including parents without children



SELECT parent.id AS ParentID,

       IFNULL(child.parent_id,') AS ChildParentID,

       IFNULL(child.id,') AS ChildID,

       IFNULL(grandchild.child_id,') AS GrandchildChildID

FROM parent

  LEFT JOIN child ON parent.id=child.parent_id

  LEFT JOIN grandchild ON child.id=grandchild.child_id;