如何在SQL中合并来自多个表的数据 [英] How to merge data from multiple tables in SQL

问题描述

猜猜我处在一个复杂的情况中.这是场景.
我在SQL Server中有3个表.
招生，学生，课程. (仅供参考，没有外键)
表格列是
学生-学生编号，学生姓名
课程-课程ID，课程名称
注册-注册ID，学生ID，课程ID，课程结果

Guess I am in a complex situation. Heres the scene.
I have 3 tables in SQL Server.
Enrollment, Student, Course. (FYI, there are no foreign keys)
The table columns are
Student - StudentId, StudentName
Course - CourseId, CourseName
Enrollment - EnrollmentId, StudentId, CourseId, CourseResult

样本数据
学生-s1，Sid
课程-C1，科学
报名-1，s1，c1，80

Sample Data
Student - s1, Sid
Course - c1, Science
Enrollment - 1, s1, c1, 80

我想要一个SQL查询，该查询选择如下所示的数据

I would want a SQL query that selects data like below

1，s1，Sid，c1，Science，80

1, s1, Sid, c1, Science, 80

我在DAL层通过多次调用数据库很难做到.但是想在一个电话中和在数据库中做到这一点.

I did it hard way in the DAL layer with multiple calls to database. But would like to do it in one call, and in DB.

任何人都可以营救！

推荐答案

使用联接.

select enrollment.*, student.*, course.* from enrollment
   inner join Student on enrollment.studentId = student.studentId
   inner join Course on enrollment.courseId = course.courseId

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