数据库中 查询结果的 并集,交集是怎么写的啊,用的什么关键字_百度知 ...

发布网友 发布时间：2022-05-07 20:48

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共4个回答

懂视网 时间：2022-05-08 01:54

MySQL没有实现Minus和Intersect功能，就像它也没有实现cube的功能一样。

可以用SQL实现同样的功能,就是麻烦了点。

drop table t1;

drop table t2;

create table t1(id int primary key,nickname varchar(20),playNum varchar(20));

create table t2(id int primary key,nickname varchar(20),playNum varchar(20));

insert into t1 values(1,1,10);

insert into t1 values(2,2,20);

insert into t1 values(3,3,30);

insert into t2 values(1,1,10);

insert into t2 values(2,2,200);

insert into t2 values(3,33,300);

commit;

MySQL实现交集

SELECT id, nickname, playNum, COUNT(*)

FROM (SELECT id, nickname, playNum

FROM t1

UNION ALL

SELECT id, nickname, playNum

FROM t2

) a

GROUP BY id, nickname, playNum

HAVING COUNT(*) > 1

MySQL实现差集

SELECT t1.id, t1.nickname, t1.playNum

FROM t1 LEFT JOIN t2 ON t1.id = t2.id

WHERE t1.nickname != t2.nickname

OR t1.playNum != t2.playNum;

热心网友 时间：2022-05-07 23:02

A 并 B 去掉重复记录----union
select empno, ename ,salary ,deptno from employee_ccy where deptno=10
union
select empno, ename ,salary ,deptno from employee_ccy where salary>100;

－－union all 不排序，不去重复

select empno, ename ,salary ,deptno from employee_ccy where deptno=10 union all
select empno, ename ,salary ,deptno from employee_ccy where salary>100;

－－－交集-----intersect
select empno, ename ,salary ,deptno from employee_ccy where deptno=10
intersect
select empno, ename ,salary ,deptno from employee_ccy where salary>100;

--差集--------minus
select empno, ename ,salary ,deptno from employee_ccy where deptno=10
minus
select empno, ename ,salary ,deptno from employee_ccy where salary>100;

-------------用两个结果集的差集 ，获得
select deptno,dname ,location from department_ccy where deptno in(select deptno from department_ccy
minus
select distinct deptno from employee_ccy );

希望对你有帮助

热心网友 时间：2022-05-08 00:20

“与”、“或”、“非”，例如交集用‘与’

热心网友 时间：2022-05-08 01:55

并集union 或 union all 前者去重后者不去重
交集intersect
差集minus
比如oracle的例子
http://wenku.baidu.com/view/0f2880bc960590c69ec37603.html