Question

我有一个基本的select查询，它正在查看表中的一些示例数据。我正在尝试获取三项信息。

总样本（总记录）
得分大于或等于85的人数
有多少分数小于85的

数据：

ScoreID RecordID    Score   ErrorMarkedToQID    ErrorActionID
1   2   30  Q00019  1
2   2   100 Q20039  3
3   3   30  Q10091  3
4   3   35  Q00019  5
6   4   5   Q10091  3

这是我尝试过的：

DECLARE @startDate DATE = '2018/09/12', @endDate DATE = '2018/09/24'

SELECT COUNT(s.ScoreID) AS totalSamples,
       COUNT(CASE WHEN s.Score >= 85 THEN 1 ELSE 0 END) AS Pass,
       COUNT(CASE WHEN s.Score < 85 THEN 1 ELSE 0 END) AS Fail
  FROM [SubmissionScores] AS s
  JOIN Submission AS sub
  ON sub.SubmissionID = s.RecordID
  WHERE sub.DateSubmittedUTC BETWEEN @startDate AND @endDate

我当前的输出是所有字段都输出5，这是记录的总数。看来我的CASE逻辑不正确。

可以像我尝试的那样通过简单的查询完成吗？

Answer 1

DECLARE @startDate DATE = '2018/09/12', @endDate DATE = '2018/09/24'

SELECT COUNT(s.ScoreID) AS totalSamples,
       COUNT(CASE WHEN s.Score >= 85 THEN 1 ELSE NULL END) AS Pass,
       COUNT(CASE WHEN s.Score < 85 THEN 1 ELSE NULL END) AS Fail
  FROM [SubmissionScores] AS s
  JOIN Submission AS sub
  ON sub.SubmissionID = s.RecordID
  WHERE sub.DateSubmittedUTC BETWEEN @startDate AND @endDate

Answer 2

Count（）函数将返回与指定条件匹配的行数，但是Case（）的结果为匹配和不匹配，因此在所有情况下都返回相同（总）的行数对于Case（）0或1，您可以使用sum（）来汇总案例的结果

 DECLARE @startDate DATE = '2018/09/12', @endDate DATE = '2018/09/24'

SELECT COUNT(s.ScoreID) AS totalSamples,
       SUM(CASE WHEN s.Score >= 85 THEN 1 ELSE 0 END) AS Pass,
       SUM(CASE WHEN s.Score < 85 THEN 1 ELSE 0 END) AS Fail
  FROM [SubmissionScores] AS s
  JOIN Submission AS sub
  ON sub.SubmissionID = s.RecordID
  WHERE sub.DateSubmittedUTC BETWEEN @startDate AND @endDate

SQL COUNT列，其中值大于value

2 个答案: