Question

CREATE TABLE PERSON
(
    persID      INT IDENTITY(1,1)   PRIMARY KEY,
    persFName   VARCHAR(30) NOT NULL,
    persLName   VARCHAR(30) NOT NULL, 
    persDOB     DATE,
    motherID    INT FOREIGN KEY REFERENCES person(persID),
    fatherID    INT FOREIGN KEY REFERENCES person(persID),
    persDOD     DATE,
    persGender  CHAR(1),
)

CREATE TABLE COUPLE
(
    coupleID    INT     IDENTITY(1,1)   PRIMARY KEY,
    alphaSpouse INT     NOT NULL    FOREIGN KEY REFERENCES person(persID),
    omegaSpouse INT     NOT NULL    FOREIGN KEY REFERENCES person(persID),
    coupleStart DATE    NOT NULL,
    coupleEnd   DATE,
)

在过去的几个小时里，我一直在努力弄清楚如何输出每个父亲，母亲和他们所有的孩子。 Trying to get an output like this

我知道如何单独显示一个组，如下所示

SELECT *
FROM person
WHERE persID IN (select fatherID from person
                    WHERE fatherID IS NOT NULL)

但我不能为我的生活弄清楚如何一起展示它们（彼此相关）。我使用交叉连接吗？联合所有？

Answer 1

这只是一次加入，好几次。它与couple表无关：

select (f.persFname + ' ' + f.persLname) as father,
       (m.persFName + ' ' + m.persLname) as mother,
       (c.persFName + ' ' + c.persLname) as child
from person c join
     person m  -- mother
     on c.motherid = m.persid join
     person f  -- father
     on c.fatherid = f.persid;

难以理解多对多递归

1 个答案: