Question

我的代码的这部分创建了一个多重查询：

$sql = "";

$sql .= "INSERT INTO projects
        (project_id, project_name, project_description, project_deadline, project_status, project_priority)
        VALUES ('" . $project_id . "', '" . $name . "', '" . $description . "', '" . $final_deadline . "', '" . $status . "', '" . $priority . "');";

foreach($assignments as $assigned_user)
{
    $sql .= "INSERT INTO assignments 
             (user_id, project_id, assigned_date) 
             VALUES ('" . $assigned_user . "', '" . $project_id . "', '" . time() . "');";
}

$result = mysql_query($sql) or die(mysql_error());

然而，我收到错误：

您的SQL语法有错误;查看与MySQL服务器版本对应的手册，以便在第3行的“INSERT INTO assignments（user_id，project_id，assigned_date）”附近使用正确的语法

然而，如果我回复$sql，结果是这样的：

INSERT INTO projects (project_id, project_name, project_description, project_deadline, project_status, project_priority) VALUES ('7090', 'Sup :D', 'OMG!', '716770800', '1', '1');
INSERT INTO assignments (user_id, project_id, assigned_date) VALUES ('12', '7090', '1284139311');
INSERT INTO assignments (user_id, project_id, assigned_date) VALUES ('11', '7090', '1284139311');

然后我手动执行SQL到PhpMyAdmin，它运行正常，但是当PHP执行它并输出错误时它怎么会不起作用？

Answer 1

mysql_query一次只能执行一个查询

试试这个：

$sql = "INSERT INTO projects
        (project_id, project_name, project_description, project_deadline, project_status, project_priority)
        VALUES ('" . $project_id . "', '" . $name . "', '" . $description . "', '" . $final_deadline . "', '" . $status . "', '" . $priority . "');";
$result = mysql_query($sql) or die(mysql_error());

foreach($assignments as $assigned_user)
{
    $sql = "INSERT INTO assignments 
             (user_id, project_id, assigned_date) 
             VALUES ('" . $assigned_user . "', '" . $project_id . "', '" . time() . "');";
    $result = mysql_query($sql) or die(mysql_error());
}

Answer 2

mysql_query函数不支持多个查询。检查mysqli :: multi_query

http://php.net/manual/en/mysqli.multi-query.php

Answer 3

学习SQL兄弟，它规则;）

$sql = "INSERT INTO assignments 
             (user_id, project_id, assigned_date) ";

foreach($assignments as $assigned_user)
{
  $sql.= " VALUES ('" . $assigned_user . "', '" . $project_id . "', '" . time() . "') ";
}

我希望你的所有变量都被转义。

Answer 4

我的猜测是mysql_query函数不允许执行多个语句，每个语句都需要单独执行。

从更大的角度来看，请考虑以下帖子：Overwriting data in a MySQL table。总之，通过在执行时连接字符串来构建查询是一种灾难，您将容易受到SQL注入攻击和其他错误的攻击。考虑使用PDO抽象层而不是调用mysql特定函数，并研究使用参数化查询而不是像你一样构建字符串。

这是初学者犯的一个标准错误（没有得到网上大量例子以及提供不良指导的书籍的帮助）所以如果你是初学者，请不要为此感到难过，请记住你不应该使用这种方法在生产系统中。

从PHP错误执行MySQL查询

4 个答案: