原文链接: http://www.linuxidc.com/Linux/2014-06/103551.htm
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;

本文通过具体的MySQL示例,展示了如何实现两个表之间的交集和差集操作。使用UNION ALL结合GROUP BY和HAVING子句来完成交集查询,而差集则通过LEFT JOIN及条件筛选实现。
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