如何从同一个数据库连接2个表？

本文介绍了如何从同一个数据库连接2个表？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我是PHP，SQL的新手，我想知道是否可以从同一个数据库连接2个表？因此，当我键入相同的课程名称时，它将从另一个表中减少1个可用座位。我的代码很乱，很抱歉 我尝试过：

i am new to PHP,SQL and i would like to know is it possible to connect 2 table from the same database ? so that when i key in the same course name , it will decrease 1 available seat from the other table. my code is in a mess sorry What I have tried:

<?php require_once ('Database.php'); $Name = mysql_real_escape_string ($_REQUEST["Name"]); $Course_applied = mysql_real_escape_string ($_REQUEST["Course_applied"]); $Email = mysql_real_escape_string ($_REQUEST["Email"]); $Contact = mysql_real_escape_string ($_REQUEST["Contact"]); $Register_Date = mysql_real_escape_string ($_REQUEST["Register_Date"]); $sql = "SELECT * FROM tblregistercourse WHERE Name = '" . $Name . "'"; $result = mysql_query ($sql, $dbconn); if (mysql_num_rows ($result) ) { $sql =("UPDATE tblcourse SET Avail_Seats = Avail_Seats-1 WHERE tblcourse.Course_Name = tblregistercourse.Course_applied"); } else { $sql = "INSERT INTO tblregistercourse (Name, Course_applied, Email, Contact, Register_Date) VALUES ('" . $Name . "', '" . $Course_applied ."', '" . $Email . "', '" . $Contact . "', '" . $Register_Date . "')"; $result = mysql_query ($sql, $dbconn); } if ($result) { $message = "Registration Successful."; echo "<script type='text/javascript'>alert('$message'); window.location='coursedetails.php';</script>"; } else $sql("UPDATE tblcourse SET Avail_Seats = Avail_Seats-1 WHERE tblcourse.Course_Name = tblregistercourse.Course_applied"); echo json_encode($resultStr); ?>

推荐答案

Name = mysql_real_escape_string（ Name = mysql_real_escape_string (

_REQUEST [Name ]）; _REQUEST["Name"]);

Course_applied = mysql_real_escape_string（ Course_applied = mysql_real_escape_string (