JOIN MySQL表

Question

我有以下表格格式：

成員

mem_id | mem_name 
    ------------------ 
    1   A 
    2   B 
    3   C 

project_members

fk_mem_id | meb_parent_id 
------------------------- 
    1   0 
    2   1 
    3   2 

，我需要像結果：

mem_id | child| parent 
-------------------------- 
    1  A  NULL 
    2  B  A 
    3  C  B 

我試過，但失敗..任何想法....？

SELECT pm.*, m1.meb_name as child, m2.meb_name as parent 
FROM members m1 
LEFT JOIN members m2 
ON m1.meb_parent_id = m2.meb_id 

Answer 1

SELECT project_members.fk_mem_id, 
     a.mem_name AS child, 
     b.mem_name AS parent 
FROM project_members 
     INNER JOIN members a 
       ON project_members.fk_mem_id = a.mem_id 
     LEFT JOIN members b 
       ON project_members.meb_parent_id = b.mem_id