SQL Query Returns Duplicate Rows - sql

Question

SELECT E.SSN AS SocialSecurityNumber ,
E.Name + ' ' + E.LastName AS FullName ,
J.Job ,
R.Date ,
R.STime AS StartTime,
R.ETime AS EndTime,
CASE WHEN R.Date BETWEEN O.SDate AND O.EDate THEN O.OffID
ELSE 0
END AS OffReason
FROM Resume AS R
INNER JOIN Employees AS E ON E.ID = R.EmpID
INNER JOIN Jobs AS J ON J.ID = E.JobID
LEFT JOIN Offs AS O ON E.ID = O.EmpID
AND R.Date BETWEEN O.SDate AND O.EDate
WHERE E.JobLeft = 0
AND R.Date BETWEEN '2014-11-26 00:00:00'
AND '2014-11-26 23:59:59'
ORDER BY FullName
I wrote this SQL Query for my employee resume report program. I want to retrieve when the employees start to work and if they have a reason for not coming to work, return the reasonId or if they don't retrieve 0. In this query, the result returns duplicate rows when there is two or more offreasons for the same employee. Like vacation & national holiday. I searched for this but can't find the same situation. The removed rows are not important; one offreason is enough for me. So I tried the DISTINCT keyword but it doesn't solve the problem. So what can I do to solve this?

Answer 1

The simplest would be to select only one of the reasons, using MAX for instance:
SELECT E.SSN AS SocialSecurityNumber,
E.Name + ' ' + E.LastName AS FullName,
J.Job,
R.DATE,
R.STime AS Start,
R.ETime AS END,
MAX(CASE
WHEN R.DATE BETWEEN O.SDate AND O.EDate THEN O.OffID
ELSE 0
END) AS OffReason
FROM Resume AS R
INNER JOIN Employees AS E
ON E.ID = R.EmpID
INNER JOIN Jobs AS J
ON J.ID = E.JobID
LEFT JOIN Offs AS O
ON E.ID = O.EmpID
AND R.DATE BETWEEN O.SDate AND O.EDate
WHERE E.Left = 0
AND R.DATE BETWEEN '2014-11-26 00:00:00' AND '2014-11-26 23:59:59'
GROUP BY E.SSN,
E.Name + ' ' + E.LastName,
J.Job,
R.DATE,
R.STime,
R.ETime
ORDER BY FullName