大力推广建设电子商务网站技术,定制网站设计公司,html5中国网站欣赏,网站开发客户挖掘相关文章 sql 的 join、left join、full join的区别图解总结#xff0c;测试#xff0c;注意事项 1. 结论示意图 对于intersect、minus#xff0c;oracle支持#xff0c;mysql不支持#xff0c;可以变通#xff08;in或exists#xff09;实现 2.测试 2.1.创建表和数…相关文章 sql 的 join、left join、full join的区别图解总结测试注意事项 1. 结论示意图 对于intersect、minusoracle支持mysql不支持可以变通in或exists实现 2.测试 2.1.创建表和数据 -- 建表 drop table if exists student; -- oralce 不支持 if exists create table student (id int ); -- 造数据4条 insert into student (id) values (1); insert into student (id) values (2); insert into student (id) values (3); insert into student (id) values (4);-- 查看表数据 select * from student;2.2.查询 2.2.1. A -- A select * from student where id in (1,2,3);2.2.1. B -- B select * from student where id in (2,3,4);2.2.3. intersect(A ∩ B)。交集。oracle支持mysql不支持可以变通实现 -- intersect(A ∩ B)。交集 select * from student where id in (1,2,3) intersect select * from student where id in (2,3,4); -- 变通实现 select * from student where id in (1,2,3) and id in ( select id from student where id in (2,3,4));2.2.4. minus(A - A ∩ B)。左差集。oracle支持mysql不支持可以变通实现 -- minus(A - A ∩ B)。左差集 select * from student where id in (1,2,3) minus select * from student where id in (2,3,4); -- 变通实现 select * from student where id in (1,2,3) and id not in ( select id from student where id in (2,3,4));2.2.5. minus(A - A ∩ B)。右差集。oracle支持mysql不支持可以变通实现 -- minus(A - A ∩ B)。右差集 select * from student where id in (2,3,4) minus select * from student where id in (1,2,3); -- 变通实现 select * from student where id in (2,3,4) and id not in ( select id from student where id in (1,2,3));2.2.6. union(A ∪ B)。并集去重 -- union(A ∪ B)。并集去重 select * from student where id in (1,2,3) union select * from student where id in (2,3,4);2.2.7. union all(A B)。和集不去重 -- union all(A B)。和集不去重 select * from student where id in (1,2,3) union all select * from student where id in (2,3,4);2.2.8. (A minus B) union (B minus A)[(A - B) (B - A)]或 (A union B) minus (A intersect B)[(A ∪ B) - (A ∩ B)] 。A ∩ B在A ∪ B的补集。oracle支持mysql不支持可以变通实现 -- 算法1(A minus B) union (B minus A)[(A - B) (B - A)]。A ∩ B在A ∪ B的补集。 ( select * from student where id in (1,2,3) minus select * from student where id in (2,3,4) ) union ( select * from student where id in (2,3,4) minus select * from student where id in (1,2,3) ); -- 算法1变通实现 ( select * from student where id in (1,2,3) and id not in ( select id from student where id in (2,3,4)) ) union ( select * from student where id in (2,3,4) and id not in ( select id from student where id in (1,2,3)) );-- 算法2(A union B) minus (A intersect B)[(A ∪ B) - (A ∩ B)] -- (union) minus (intersect)[(A ∪ B) - (A ∩ B)]。A ∩ B在A ∪ B的补集。 ( select * from student where id in (2,3,4) union select * from student where id in (1,2,3) ) minus ( select * from student where id in (2,3,4) intersect select * from student where id in (1,2,3) ); -- 算法2变通实现 select * from ( select * from student where id in (1,2,3) union select * from student where id in (2,3,4) ) where id not in ( select id from student where id in (1,2,3) and id in ( select id from student where id in (2,3,4)) );