Question

我正在尝试为districtIDNum = 5中已完成courseIDNum=11或courseIDNum=12但未同时完成的人员提供数据。

然而，在我执行查询后，它返回所有区。我做错了什么？请帮助，并提前感谢！

SELECT p.FirstName, p.LastName, p.Email, s.CourseIDNum
FROM People p
INNER JOIN Registration r
 on p.PeopleID = r.PeopleIdNum
INNER JOIN Section s
 on r.SectionIDNum = s.SectionID
INNER JOIN School sc
 on p.SchoolIDNum = sc.SchoolID
WHERE (s.CourseIDNum=11 AND s.CourseIDNum!=12)
  OR (s.CourseIDNum!=11 AND s.CourseIDNum=12)
  AND s.DistrictIDNum=5
  AND r.Completed='Y'

以下是涉及的表格：

的peopleid名姓电子邮件schoolIDNum
1埃丝特乙b@hotmail.com 33
2托米大号l@hotmail.com 55

registrationID peopleIDNum sectionIDNum
22个1 40
23 2 41

sectionID courseIDNum districtIDNum
40个11 5
41 12 5

schoolID districtIDNum
33个5
55 5

Answer 1

要仅返回参加其中一门课程而非两门课程的人，请尝试：

SELECT max(p.FirstName), 
       max(p.LastName), 
       max(p.Email), 
       max(s.CourseIDNum)
FROM People p
INNER JOIN Registration r
 on p.PeopleID = r.PeopleIdNum
INNER JOIN Section s
 on r.SectionIDNum = s.SectionID
INNER JOIN School sc
 on p.SchoolIDNum = sc.SchoolID
WHERE s.CourseIDNum IN (11, 12)
   AND s.DistrictIDNum = 5
   AND r.Completed='Y'
group by p.PeopleID
having count(distinct s.CourseIDNum)=1

SQLFiddle here。

SQL Query返回所有区域的结果，但我只需要显示一个区域

1 个答案: