Question

我有一个这样的数据库表

Table student
_______________
id_student int (PK)
student_name VARCHAR

，我有一个递归循环：一个学生可以监督许多学生，而一个学生可以被许多学生监督所以有一张新桌子：

Table oversee
________________
id_student pk, fk 
id_overseen pk, fk
date date

问题是我想获取我拥有的列表我做了一个SQL查询：

with 
sr1 as ( select s.student_name as over from student s, oversee o where o.id_student = s.id_student),
sr2 as (select s.student_name as overseen from student s, oversee o where o.id_overseen = s.id_student)
select distinct * from sr1, sr2;

问题是查询返回错误的答案我的意思是，如果表中有两行，它将返回4行。我想让每个学生都受到他的监督：学生|监督。有人有什么主意吗？谢谢。

Answer 1

我想用student | overseen | date
来获得一张桌子

SELECT s.student_name AS student
     , s2.student_name AS overseen
     , oversee.date
  FROM student s
  JOIN oversee ON oversee.id_student = s.id_student
  JOIN student s2 ON s2.id_student = oversee.id_overseen

SQLite中的递归SQL查询N至N

1 个答案: