Question

是否可以永久加入两个表？我只是在执行该查询后执行，之后即使退出DBMS，它也可以自动加入？

Answer 1

您可能需要考虑创建view。

视图本质上是一个存储的SQL语句，您可以像查询表一样进行查询。

create view MyView as
    select TableA.Field1, TableB.Field2
    from TableA
    join TableB on TableB.ID = TableA.ID


select *
from MyView

Answer 2

如果您总是同时写入并从联接中读取，则可以将它们合并为一个并从中进行编写和选择。

--==[ before ]==--
insert into user (id, name) values (1, "Andreas");
insert into email (id, email) values (1, "andreas - at - wederbrand.se");

select user.id, user.name, user.email from user, email where user.id = email.id;

--==[ do the merge ]==--
create table user_with_email select user.id, user.name, user.email from user, email where user.id = email.id;

drop table user;
drop table email;

--==[ after ]==--
insert into user_with_email id, name, email values (2, "Bruce", "Bruce - at - springsteen.com");

select id, name, email from user_with_email;

如何使用SQL永久连接两个表？

2 个答案: