如何在两个表上使用联合 [英] how to use union on two tables

问题描述

我必须在表中列出时间表和员工.
时间表表中包含employeeid，startdate，enddate列和
员工表包含employeeid，employeename列.
现在，如果我想知道在特定日期没有填写时间表的员工名称.

在此先感谢.

I have to tables name timesheet and employee.
where timesheet table contains employeeid,startdate,enddate columns and
employee table contains employeeid,employeename columns.
now if i want to know the employeename who has not fill the timesheet on a particular day.

Thanks in Advance.

推荐答案

首先，我想告诉您，无需使用UNION即可得到这样的结果.

您在这里解决方案:

Hi,

First of all i would like to tell you that no need to use UNION to get such result.

You Solution Here:

SELECT * FROM Employee WHERE EmployeeID NOT IN (SELECT EmployeeID FROM TimeSheet WHERE StartDate>='YYYY-MM-DD' AND EndDate<='YYYY-MM-DD')

Select e.employeename 
from employee e join timesheet t 
where e.employeeid=t.employeeid
and t.startdate is null 
or t.enddate is null

嘿，
试试这个

Hey,
Try this

select employeename from employee emp inner join timesheet ts on emp.employeeid =ts.employeeid
where startdate=null or enddate=null

祝你好运

Good Luck

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