多个INNER JOIN SQL访问语法

Question

我正在尝试使用table(six_attendance, five_attendance)通过INNER JOIN从table(users)获取数据。这是我尝试过的：

$query = mysql_query("SELECT * 
FROM
(users 
INNER JOIN six_attendance 
ON users.username = six_attendance.username)
INNER JOIN five_attendance 
ON users.username = five_attendance.username
WHERE six_attendance.username OR five_attendance.username ='$reg_no'");

Answer 1

$query = mysql_query("SELECT * 
FROM
users 
INNER JOIN six_attendance 
ON users.username = six_attendance.username
INNER JOIN five_attendance 
ON users.username = five_attendance.username
WHERE six_attendance.username='$reg_no' OR five_attendance.username ='$reg_no'");