mysql和php的整数值不正确

我收到以下错误消息：

插入数据时出错。请稍后重试。（第98行）第1行“主题”列的整数值“”不正确

这是我的代码：

<?php
//create_cat.php
include 'connect.php';
include 'header.php';

echo '<h2>Create a topic<h2>';

/*
if(isset($_SESSION['signed_in']) == false)
{
    //the user is not signed in
    echo 'Sorry, you have to be <a href="signin.php">signed in</a> to create a topic.';
}
else
{
 */
    //the user is signed in
    if($_SERVER['REQUEST_METHOD'] != 'POST')
    {
        //the from hasn't been posted yet, display it
        //retrieve the categories from the database for use in the dropdown
        $sql = "SELECT
                    cat_id,
                    cat_name,
                    cat_description
                FROM
                    categories";

        $result = mysql_query($sql);

        if(!$result)
        {
            //the query failed, uh-oh :-(
            echo 'Error while selecting from database. Please try again later.';
        }
        else
        {
            if(mysql_num_rows($result)==0)
            {
            //there are no categories, so a topic can't be posted
            if($_SESSION['user_level']==1)
            {
                echo 'You have not created categories yet.';
            }
            else
            {
                echo 'Before you can post a topic, you must wait for an admin to create some categories.'; 
            }
        }
        else
        {
            echo '<form method="post" action="">

                Topic By: <input type="text" name="topic_by" />
                Category:';

            echo '<select name="topic_cat">';
                while($row = mysql_fetch_assoc($result))
                {
                    echo '<option value="'
                    .$row['cat_id'].'">'
                    .$row['cat_name'].
                    '</option>';
                }
            echo '</select>';

            echo 'Message: <textarea name="post_content" /></textarea>
            <input type="submit" value="Create topic" />
            </form>';
        }
    }
}
else
{
    //start the transaction
    $query = "BEGIN WORK;";
    $result = mysql_query($query);

    if(!$result)
    {
    //Damn! the query failed, quit
    echo 'An error occured while creating your topic. Please try again later.';
    }
    else
    {
    //the form has been posted, so save it
    //insert the topics table first, then we'll save the post into the posts table
    $sql = "INSERT INTO
            topics(topic_subject,
                topic_date,
                topic_cat,
                topic_by)
    VALUES('" . mysql_real_escape_string($_POST['topic_subject']) . "',
                NOW(), 
            '" . mysql_real_escape_string($_POST['topic_cat']) . "',
            '" . $_SESSION['user_id'] . "'
                )";

    $result = mysql_query($sql);
    if(!$result)
    {
    //something went wrong, display the error
    echo 'An error occured while inserting your data. Please try again later.(line 98)'.mysql_error();
    $sql = "ROLLBACK;";
    $result = mysql_query($sql);
}
else
{
    //the first query worked, now start the second, posts query
    //retrieve the id of the freshly created topic for usage in the posts query
    $topicid = mysql_insert_id();

    $sql = "INSERT INTO
                posts(post_content,
                        post_date,
                        post_topic,
                        post_by)
            VALUES
                ('". mysql_real_escape_string($_POST['post_content'])."',
                NOW(),
                ".$topicid.",
                ".$_SESSION['user_id']."
                )";
    $result = mysql_query($sql);

    if(!$result)
    {
    //something went wrong, display the error
    echo 'An error occured while inserting your post. Please try again later.(line 124)'.mysql_error();
    $sql = "ROLLBACK;";
    $result = mysql_query($sql);
    }
    else
    {
    $sql = "COMMIT;";
    $result = mysql_query($sql);

    //after a lot of work, the query succeeded!
    echo 'You have successfully created <a href="topic.php?id='.$topicid.'">your new topic</a>.';
                }
            }
        }
    }
//}

include 'footer.php';
?>

---

问题不在于数据周围的引号，而在于
$\u SESSION['user\u id']
可能返回为空白或空。MySQL会将“”解释为空字符串而不是int。因此请删除qoutes

$sql = "INSERT INTO
        topics(topic_subject,
            topic_date,
            topic_cat,
            topic_by)
VALUES('" . mysql_real_escape_string($_POST['topic_subject']) . "',
            NOW(), 
        '" . mysql_real_escape_string($_POST['topic_cat']) . "',
        " . $_SESSION['user_id'] . " )";  //Remove the qoutes

最新答复：

看起来您在运行MySQL时启用了SQL严格模式

要禁用严格模式，请在编辑器中打开my.cnf并删除/注释掉以下行：

sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"

然后重新启动数据库服务器。
同时检查您的状态！结果

if(!result)
{

}
else
{

}
else
{

}

2.否则的话就错了
像这样做
if（）{}else if（）{}else{}
尝试回显$\u SESSION['user\u id']的val，并检查它是否为int。我已经尝试过了，我收到了以下错误消息：插入数据时发生错误。请稍后再试。（第98行）您的SQL语法有错误；查看与MySQL服务器版本相对应的手册，以了解第9行中使用的正确语法（接近“）”。看起来最接近my.cnf的页面是“my default.ini”。我注释掉了文件结尾的一行“#sql mode=NO_ENGINE_SUBSTITUTION_TRAN_TABLES。我仍然在第9行收到错误消息“检查MySql服务器版本以获得正确的语法以使用near”）。请尝试签入
/etc/my.cnf