在mysql中内联接3个表 [英] Inner join with 3 tables in mysql

问题描述

我想从更多的表中选择内部连接的数据。

I want to select data from more tables with Inner join.

这是我的表。

Student (studentId, firstName, lastname)
Exam (examId, name, date)
Grade (gradeId, fk_studentId, fk_examId, grade)

我要写一份声明，说明学生已经参加的考试，年级和日期。

I want to write a statement that shows which exam, grade and date alle the students have been to. Sorted after date.

这是我的陈述。它运行，但我想确保我做的正确。

This is my statement. It runs, but i want to make sure that i am doing it correctly.

SELECT
  student.firstname,
  student.lastname,
  exam.name,
  exam.date,
  grade.grade
FROM grade
  INNER JOIN student
    ON student.studentId = grade.gradeId
  INNER JOIN exam
    ON exam.examId = grade.gradeId
ORDER BY exam.date

推荐答案

几乎正确..看看连接，你指的是错误的字段

Almost correctly.. Look at the joins, you are referring the wrong fields

SELECT student.firstname,
       student.lastname,
       exam.name,
       exam.date,
       grade.grade
  FROM grade
 INNER JOIN student ON student.studentId = grade.fk_studentId
 INNER JOIN exam ON exam.examId = grade.fk_examId
 ORDER BY exam.date

这篇关于在mysql中内联接3个表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！