mysql - mysql中3个表的内连接

Question

我想使用内连接从更多表中选择数据。

这些是我的 table 。

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

我想写一份声明，说明学生参加过的考试、年级和日期。按日期排序。

这是我的声明。它运行，但我想确保我做的正确。

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

Answer 1

几乎正确.. 看看连接，你指的是错误的字段

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