Mysql SQL查询，从一个表中选择不在另一个表中的行

注册和集团成员

Registration Table
id  name  
-------                
1   A    
2   B    
3   C
4   D

group_members Table
name  Gid 
-------                
A   01    
B   01    
C   02

我需要从注册表中获取姓名，这些姓名不是组成员表中的成员，Gid为02。 输出必须明显A、B和D。 但我不知道如何做到这一点。请帮助。谢谢尝试以下方法：

SELECT t1.*
FROM Registration AS t1
LEFT JOIN Group_members AS t2 ON t1.name = t2.name AND t2.Gid = '02'
WHERE t2.name IS NULL 

这将过滤掉

group\u members

表中带有

Gid='02'

的所有匹配记录，请尝试以下操作：

SELECT t1.*
FROM Registration AS t1
LEFT JOIN Group_members AS t2 ON t1.name = t2.name AND t2.Gid = '02'
WHERE t2.name IS NULL 

这将过滤掉

group\u members

表中与

Gid='02'

匹配的所有记录，这应该可以工作

select name from
Registration reg where 
not exists 
(select null 
from group_members gm
where gm.name = reg.name
and gm.gid = '02')

这应该行得通

select name from
Registration reg where 
not exists 
(select null 
from group_members gm
where gm.name = reg.name
and gm.gid = '02')