[英]SQL Select to display one to one, one to many from many to many relation
[英]SQL one to many from many to many relation
我正在尝试找出 SQL 查询,该查询将仅列出一对多关系
下表包含 11 条记录,我想返回两行 Field1 = 7(一对多)
表格1:
Field1 Field2
1 a
2 a
3 b
4 b
5 c
4 d exclude 4 and 6 as d is linked to both
6 d
6 e
7 f One to Many
7 j One to Many
8 g
您希望每个field1
的所有field2
值都出现一次。 这是一个使用 window 函数的方法:
select field1
from (select t.*,
count(*) over (partition by field2) as num_field2
from t
) t
group by field1
having count(*) > 1 and max(num_field2) = 1;
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.