Question

我具有基本的SQL知识，并且尝试编写以下问题的SQL语句：

Q：列出所有具有麻疹免疫力的学生[在此处输入图像描述] [1]，但对水痘有宗教豁免。

我所拥有的：
宗教豁免

dragend

患有麻疹疫苗的人

clientY

我不确定如何将两者结合以获得单个结果。

附加的是数据库的逻辑模型。
[1]：https://i.stack.imgur.com/UQGqC.png

Answer 1

如果要将代码保留在上面，则可以扩展JOIN和WHERE条件

SELECT DISTINCT(P.personID)
FROM Person P
INNER JOIN Waiver ON Person.personID = Waiver.personID
INNER JOIN WavierDisease On Waiver.waiverID = WaiverDisease.waiverID
INNER JOIN Disease ON WaiverDisease.diseaseID = Disease.diseaseID
INNER JOIN Immunity ON Person.personID = Immunity.personID -- add this
WHERE
Disease.diseaseName = ‘Chickenpox’
AND Waiver.exemptCode = ‘Religious’
AND Immunity.diseaseId IN ( -- add this
   SELECT diseaseId FROM Disease WHERE Disease.diseaseName = 'Measles'
)

Answer 2

要有效回答问题，

Q：列出所有具有麻疹免疫力但对水痘有宗教豁免的学生。

您需要查询两个条件：1）麻疹免疫力和2）水痘（或水痘）的宗教豁免。

因此，考虑将JOIN添加为另一个Disease，并第二次联接到SELECT P.* FROM Person p INNER JOIN Waiver w --- WAIVER CHECK ON w.personID AND p.personID AND w.exemptCode = 'Religious' INNER JOIN WavierDisease wd ON wd.waiverID = w.waiverID INNER JOIN Disease d1 ON d1.diseaseID = wd.diseaseID AND d1.diseaseName = 'Chickenpox' INNER JOIN Immunity i --- IMMUNITY CHECK ON i.personID AND p.personID INNER JOIN Disease d2 ON d2.diseaseID = i.diseaseID AND d2.diseaseName = 'Measles'表中：

make_token

Answer 3

列出所有拥有...的学生

“列出所有学生”是指从“学生”表中选择。（我猜您的桌子是“人”吗？或者也许只有那个桌子中的某些人？）
“具有...”的意思是WHERE ...。而且，由于该信息位于其他表中，因此您需要EXISTS或IN。

如果我正确理解了您的数据模型，这将为我们带来帮助：

select *
from person
where personid in 
(
  select personid
  from immunity
  where diseaseid = (select diseaseid from disease where diseaseName = 'Measles')
)
and personid in
(
  select personid
  from waiver
  where exemptCode = 'Religious'
  and waiverid in 
  (
    select waiverid
    from waiverdisease 
    where diseaseid = (select diseaseid from disease where diseaseName = 'Chickenpox')
  )
);

我认为这是可读的。而且由于使用IN而不是联接，因此我们确保不要在查找中得到任何重复项。

Answer 4

您可以使用union

SELECT *
FROM Person P
INNER JOIN Waiver ON Person.personID = Waiver.personID
INNER JOIN WavierDisease On Waiver.waiverID = WaiverDisease.waiverID
INNER JOIN Disease ON WaiverDisease.diseaseID = Disease.diseaseID
WHERE Disease.diseaseName = ‘Chickenpox’
AND Waiver.exemptCode = ‘Religious’
union
SELECT *
FROM Immunity I
INNER JOIN Disease ON I.diseaseID = Disease.diseaseID
WHERE Disease.diseaseName = 'Measles';

Answer 5

我让它起作用。感谢您的快速帮助。

SELECT Immunity.personID
FROM Immunity
INNER JOIN Disease ON Immunity.diseaseID = Disease.diseaseID
WHERE Disease.diseaseName = 'Measles'
UNION
SELECT Person.personID
FROM Person
INNER JOIN Waiver ON Person.personID = Waiver.personID
INNER JOIN WaiverDisease On Waiver.waiverID = WaiverDisease.waiverID
INNER JOIN Disease ON WaiverDisease.disease = Disease.diseaseID
WHERE Disease.diseaseName = 'Chickenpox'
AND Waiver.exemptTypeCode = 'Religious';

组合两个SQL Select语句

5 个答案: