如何从特定日期在另一个表中不存在的一个表中获取ID [英] how get id from one table which does not exists in another table on specific date

问题描述

我想从出勤系统表中获取ID，但该ID在特定日期不存在，这意味着该日期没有输入.
我如何从该日期的注册表中获取ID

i want get id from table for attendance system which is not present on specific day means doesn`t have entry to that day.
how do i get id from registration table for that date

推荐答案

我认为Sql Server的NOT IN子句与Sub Query一起可以用于上述内容目的如下

I think the NOT IN Clause of Sql Server in conjunction with Sub Query can be used for the above purpose as below

SELECT Id 
FROM RegistrationTable
WHERE Id NOT IN (
    SELECT Id 
    FROM AttendanceTable
    WHERE Date = --Enter Required Date literal or variable here
)

如果RegistrationTable包含来自AttendaceTable的PK(主键)的FK(外键)，请尝试以下操作:

If RegistrationTable contains FK (Foreign Key), which comes from AttendaceTable as a PK (Primary Key), try this:

SELECT RT.RegistrationID
FROM RegistrationTable AS RT LEFT JOIN AttendanceTable AS AT ON RT.AttendanceID = AT.AttendanceID
WHERE NOT RT.Date IS NULL AND AT.Date IS NULL
--or any other value

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