显示表格和给定日期范围中不存在的记录

Question

假设我有两个表 - 学生和学生出勤表。 Student 表显示有关学生的基本信息：

Student#	FirstName	LastName
201710	John	Smith
201711	John	Doe
201712	Anna	Sy
201713	Chris	Dy

虽然学生出勤表显示学生上课的时间进出时间：

Student#	Date	TimeIn	TimeOut
201710	2016-01-06	00:09:00.000	00:15:00.000
201711	2016-01-06	00:09:10.000	00:15:00.000
201712	2016-01-06	00:09:05.000	00:15:00.000
201713	2016-01-06	00:09:00.000	00:15:00.000
201710	2016-01-07	00:09:00.000	00:15:00.000
201711	2016-01-07	00:09:10.000	00:15:00.000
201712	2016-01-07	00:09:05.000	00:15:00.000
201710	2016-01-08	00:09:00.000	00:15:00.000
201712	2016-01-08	00:09:10.000	00:15:00.000
201713	2016-01-08	00:09:05.000	00:15:00.000

我的目标是还包括当天没有日志的学生的学生编号，我将使用它来确定他们是否缺席。

Student#	Date	TimeIn	TimeOut
201710	2016-01-06	00:09:00.000	00:15:00.000
201711	2016-01-06	00:09:10.000	00:15:00.000
201712	2016-01-06	00:09:05.000	00:15:00.000
201713	2016-01-06	00:09:00.000	00:15:00.000
201710	2016-01-07	00:09:00.000	00:15:00.000
201711	2016-01-07	00:09:10.000	00:15:00.000
201712	2016-01-07	00:09:05.000	00:15:00.000
201713	NULL	NULL	NULL
201710	2016-01-08	00:09:00.000	00:15:00.000
201711	NULL	NULL	NULL
201712	2016-01-08	00:09:10.000	00:15:00.000
201713	2016-01-08	00:09:05.000	00:15:00.000

感谢您的帮助！

Answer 1

首先您需要创建一个日历表来填充所需的日期，然后使用Students 表在CROSS JOIN 它。

之后，将StudentsAttendance 表与结果集左连接。

日历表：

CREATE TABLE #Cal(AttDate DATE)
DECLARE @MinDate DATE = '2016-01-06', @MaxDate DATE = '2016-01-08'

WHILE @MinDate<=@MaxDate
BEGIN
    INSERT INTO #Cal
    SELECT @MinDate

    SET @MinDate = DATEADD(DAY,1,@MinDate)
END

此表包含以下日期。

AttDate
2016-01-06
2016-01-07
2016-01-08

现在执行查询

SELECT D.Student#,D.AttDate,SA.TimeIn, SA.TimeOut
FROM(
    SELECT S.Student#, AttDate
    FROM #Cal C
    CROSS JOIN Student S
    )D
LEFT JOIN Student_Attendance SA ON SA.Student# = D.Student# AND SA.Date = D.AttDate
ORDER BY D.AttDate,D.Student# 

试试这个，如果您遇到任何错误，请告诉我们。

SQLFiddle