Merge duplicate temporal records in database

Question

I have a temporal database table where some of the data is duplicated.

EmployeeId   StartDate   EndDate     Column1   Column2
1000         2009/05/01  2010/0         


        

Answer 1

Try this

SELECT A.EmployeeId,A.StartDate,A.EndDate,A.Column1,A.Column2 FROM (SELECT EmployeeId,StartDate,EndDate,Column1,Column2 FROM TEMP GROUP BY EmployeeId,StartDate,EndDate,Column1,Column2)A
JOIN 
(SELECT Y.EmployeeId,Y.StartDate,Y.EndDate,Y.Column1,Y.Column2 FROM TEMP X JOIN TEMP Y ON X.EmployeeId=Y.EmployeeId AND DATEADD(day,1,X.EndDate)=Y.StartDate)B 
ON A.EndDate=DATEADD(day,-1,B.StartDate)

Note: TEMP is the table with mentioned columns