create table Person(
SSN INT,
Name VARCHAR(20),
primary key(SSN)
);
create table Car(
PlateNr INT,
Model VARCHAR(20),
primary key(PlateNr)
);
create table CarOwner(
SSN INT,
PlateNr INT,
primary key(SSN, PlateNR)
foreign key(SSN) references Person (SSN),
foreign key(PlateNr) references Car (PlateNr)
);
Insert into Person(SSN, Name) VALUES ('123456789','Max');
Insert into Person(SSN, Name) VALUES ('123456787','John');
Insert into Person(SSN, Name) VALUES ('123456788','Tom');
Insert into Car(PlateNr, Model) VALUES ('123ABC','Volvo');
Insert into Car(PlateNr, Model) VALUES ('321CBA','Toyota');
Insert into Car(PlateNr, Model) VALUES ('333AAA','Honda');
Insert into CarOwner(SSN, PlateNr) VALUES ('123456789','123ABC');
Insert into CarOwner(SSN, PlateNr) VALUES ('123456787','333AAA');
我遇到的问题是我想做的SELECTE查询。我不能从人物中选择所有东西,而不是包括他所拥有的汽车的PlateNr,例如:
PERSON
---------------------------------
SSN NAME Car
123456789 Max 123ABC
123456787 John 3338AAA
123456788 Tom
----------------------------------
所以,我希望能够显示Person表中的所有内容并显示CarOwner的内容,以及该人是否实际上是CarOwner。到目前为止我所拥有的是:“SELECT * from Person,CarOwner WHERE Person.SSN = CarOwner.SSN;”。但这显然导致只显示CarOwners的人。
希望我能很好地解释我,谢谢。
答案 0 :(得分:2)
试试这个:
SELECT p.*, c.*
FROM Person p
LEFT OUTER JOIN CarOwner co
ON p.SSN = co.SSN
LEFT OUTER JOIN Car c
ON co.PlateNr = c.PlateNr
P.S。我已经更改了主键PlateNr的类型(在varchar而不是在int中)
答案 1 :(得分:1)
选择ssn,name,car
来自Person p
LEFT OUTER JOIN CarOwner co </ p>
ON p.SSN = co.SSN
LEFT OUTER JOIN Car c
ON co.PlateNr = c.PlateNr