SQL查询返回重复行

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 

我为我的员工简历报告程序编写了此SQL查询。我想在员工开始工作时检索，如果他们有工作不上班的原因，则返回reasonId或者如果他们没有检索到0。在此查询中，当存在两个或更多非理由时，结果返回重复行为同一名员工。像假期&国定假日。我搜索了这个，但无法找到相同的情况。删除的行不重要;一个不合理的情况对我来说已经足够了。所以我尝试了DISTINCT关键字，但它不能解决问题。那么我能做些什么来解决这个问题？

Answer 1

最简单的将是唯一的选择的原因之一，采用MAX例如：

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