如何加入两个表？ [英] How to join two tables?

问题描述

假设两个表都不是普通字段并且没有任何关系......你怎么能加入那两个表..？



表名是EMP

Suppose if both table do not common field and don't have any relation......how can you join that two tables..?

Table name is EMP

EMPNO   NAME    JOB
1       SAM    CLERK
2       RAM    ACCOUNT
3       PRABU   CLERK
4       RAJ     MANAGER

表名是DEPT

Table name is DEPT

DEPTNO   DNAME      LOC
10       ACCOUNT     UK
20       ANALYST     US
30       RESEARCH    JAPAN

推荐答案

您不希望加入两个没有任何共同点的表格。 />
你仍然可以做的是一个CROSS-JOIN，它将列出所有行的组合 - CROSS-JOIN [ ^ ]。

You would not want to join two tables that have nothing in common.
What you can still do is a CROSS-JOIN that will list out all combination of rows - CROSS-JOIN[^].

员工肯定必须属于某些部门，他们是empl oyees。所以在emp表中添加一个deptno列并将其链接到dept表中的deptno，现在你就拥有了这个关系。

阅读更多：数据库设计简介 [ ^ ]

Employees surely have to belong to some departments else they are employees. So add a column "deptno" in the "emp" table and link it to the "deptno" in the "dept" table, and now you have the relationship.
Read more: Introduction to database design[^]

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