A key thing to notice here is the existence of a DEPTID column in both tables.
这里需要重点注意的是，在both表中有一个deptid列。
Using JoinRowSet lingo, our JOIN operation was performed using a match column of DEPTID.
在使用JoinRowSet lingo时，JOIN操作是通过匹配列deptid来执行的。
Query 19 returns the deptID of those departments which have a unit manager among their employees.
查询 18返回其员工中包含单位主管的那些部门的deptID。
As you can see, I have specified a match column of DEPTID for both the employees and departments objects.
您可以看到，对于employees和departments对象，我都指定了匹配列DEPTID。
Similarly, we do not see a row containing the DEPTID named TRA since no employee in the employee table had a DEPTID of TRA.
类似地，我们也没有看到包含名为TRA的DEPTID的行，因为在employee表中没有DEPTID为TRA的雇员。
This effectively combined the data contained in our two tables (EMPLOYEE and DEPARTMENT) based upon a common attribute (the DEPTID value).
这样便基于一个相同的属性(deptid值)将两个表(EMPLOYEE和DEPARTMENT)中的数据有效地组合起来。
This effectively combined the data contained in our two tables (EMPLOYEE and DEPARTMENT) based upon a common attribute (the DEPTID value).
这样便基于一个相同的属性(deptid值)将两个表(EMPLOYEE和DEPARTMENT)中的数据有效地组合起来。
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