mysql，通过分页获取树评论（邻接列表）

Question

I have read a lot of information about mysql tree adjacency list

I want to display the 10 most recent comments and ALL replies to this comment ( or where 10 comments where parentId is null and level = 1 but take all comments where exists parentId and level = 2 )

my table with data:

mysql comments table

Answer 1

You can use Common Table Expressions . Similar to the following code :

WHIT 
    CTE1 AS (SELECT * FROM comments WHERE parentId is null and level = 1)
SELECT * FROM CTE1 
UNION ALL
SELECT * FROM Comments WHERE parentId IN (SELECT id FROM CTE1) AND level = 2