SQL-内连接（Inner join）

SQL INNER JOIN 语法:

SELECT column_name(s)
FROM table1
INNER JOIN table2
ON table1.column_name=table2.column_name;

或

SELECT column_name(s)
FROM table1
JOIN table2
ON table1.column_name=table2.column_name;

示例：

SELECT student.StudentId,student.StudentName,student_class.ClassID
FROM student
LEFT JOIN student_class
ON student.StudentId = student_class.StudentID
ORDER BY student.StudentId DESC;

注释：INNER JOIN 关键字在表中存在至少一个匹配时返回行。如果 “Websites” 表中的行在 “access_log” 中没有匹配，则不会列出这些行。