从表B中删除，其中表A中不存在值

Question

I am trying to accomplish the following in MySQL:

delete from table_b where table_b.token is not found in table_a.token 

Explanation:

Both tables have a column called token .

I want to delete all records on table_b if token in table_b does not exist in the token column in table_a.

Answer 1

You can use a join

delete b.*
from table_b b
left join table_a a on(b.token = a.token)
where a.token is null

Answer 2

使用子查询：

delete from table_b where token not in (select token from table_a)