测试用例表如下：
1.取2个成员表中的交集（A∩B）
T-SQL:
select Member1.Name,Member1.Age from Member1 join Member2 on Member1.Name=Member2.Name
select * from Member1
intersect
select * from Member2
2.取2个成员表中的并集（A∪B）
T-SQL:
select * from Member1
union
select * from Member2
3.取在A中不在B中（A-B）
T-SQL:
select * from Member1 left join Member2 on Member1.Name=Member2.Name
where Member2.Name is null
---或者使用full join
select * from Member1 full join Member2 on Member1.Name=Member2.Name
where Member2.Name is null
4.取在B中不在A中（B-A）
T-SQL:
select * from Member1 right join Member2 on Member1.Name=Member2.Name
where Member1.Name is null
---或者使用full join
select * from Member1 full join Member2 on Member1.Name=Member2.Name
where Member1.Name is null
5.full join = 1+3+4
T-SQL:
select * from Member1 full join Member2 on Member1.Name=Member2.Name
6.except =3 or 4
T-SQL:
select * from Member1
except
select * from Member2
7.union all(合并包含重复项) =2+1
T-SQL:
select * from Member1
union all
select * from Member2
8.交叉连接 =表A*表B
T-SQL:
select * from Member1 cross join Member2
---等同于
select * from Member1,Member2
select * from Member1 join Member2 on 1=1
一幅简图更好地理解表联接：