有两个表
Table A
id column_a
01 abc
01 abc
02 abc
02 abc
02 abc
03 abc
03 abc
04 abc
表 B
id column_b
01 abc
02 abc
02 abc
03 abc
04 abc
我想比较上面的两个表,并在表 a 中得到结果,但不在表 b 中得到结果,例如:
id column_a
01 abc
01 abc
02 abc
03 abc
如何在 MySQL 中做到这一点?
多谢!
更新
SELECT A.* FROM A
LEFT JOIN B ON A.column_a = B.column_b AND A.id = B.id
WHERE B.id IS NULL
尝试
SELECT A.* FROM A
LEFT JOIN B ON A.ID=B.ID AND A.column_a=B.column_b
WHERE B.ID IS NULL
问候
试试这个:
select a.id,a.column_a
from (select count(*) as a_num, id,column_a
from table_a group by id having count(*) > 1) as a
left join (select count(*) as b_num, id from table_b group by id having count(*) > 1) as b
on a.a_num > b.b_num;