Question

编写SQL查询以列出未提交任何所需评估的受训人员的所有培训生，姓名和电子邮件。

我的尝试：

SELECT TraineeId
,      fname
,      lname
,      e-mail
FROM   Trainee T
,      assessment A
,      submissions S
WHERE  NOT EXISTS (A.assessmentId = S.assessmentId AND A.courseId = S.courseId) 
   AND T.traineeId = S.traineeId;

我不太确定这个问题。该代码试图找到两个表之间的交集。

此外，创建一个查询，以便为迟到的提交扣除5％

它是否顺利：WHERE A.submissionDeadline＆gt; S.submissionDate;

注意：这是来自练习考试，没有解决方案;这不是功课。

感谢您的帮助。

Answer 1

可以解决您的问题

SELECT 
     T.TraineeId, T.fname, T.lname, T.e-mail
FROM 
     Trainee T, 
join  
    submissions S 
on 
    T.TraineeID = S.TraineeID 
join 
    assessment A
on
    S.AssessmentId=A.AssessmentId
WHERE condition

Answer 2

SELECT `TraineeId`, `fName`, `lName`, `email`
FROM trainee T
WHERE TraineeId NOT IN (
  SELECT S.TraineeId 
  FROM submissions S, assessment A
  WHERE A.assessmentId = S.assessmentId 
  AND A.courseId = S.courseId
  AND A.submissionDeadline >= S.submissionDate)

低级SQL查询

2 个答案: