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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