php - 插入MySQL "on duplicate key update"语法错误

Question

$sql = "INSERT INTO couponentries (itemid, coupon, MSISDN, channel, result) 
       VALUES ('".$itemid."','".$CouponCode."', '".$MSISDN."','".$channel."','".$status."')
       ON DUPLICATE KEY UPDATE couponentries.result = VALUES('Invalid couponcode[ERR: Already exists]')";

我正在尝试将新项目从 PHP 网络表单插入到 MySQL 数据库。如果我插入重复的行，我会将结果更新为一条错误消息。这是我的代码。它一直给我一个语法错误。

ERROR: Could not able to execute You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''Invalid couponcode[ERR: Already exists]')' at line 3

Answer 1

您正在使用字符串文字来更新您的列 - 丢失值:

$sql = "INSERT INTO couponentries (itemid, coupon, MSISDN, channel, result) 
       VALUES ('".$itemid."','".$CouponCode."', '".$MSISDN."','".$channel."','".$status."')
       ON DUPLICATE KEY UPDATE couponentries.result = 'Invalid couponcode[ERR: Already exists]'";

强制性旁注:
像这样连接字符串会使您的代码容易受到 SQL 注入(inject)攻击。你应该看看 Prepared Statements相反。