php - PHP:检查mysql中是否存在行

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How to check if a row exists in MySQL? (i.e. check if an email exists in MySQL)
                                
                                    （4个答案）
                                
                        
                                2年前关闭。
            
                    
为了在数据库中准备重复的条目，我想检查ID是否存在于MYSQL表中，但是如果插入多行，我不知道如何检查它。

这是我的代码：

    if(is_array($newdata)){

    $sql = "INSERT INTO `events` (eventid, eventname, eventstart, eventend, coverid, coverurl, placeid, placename, city, country, latitude, longitude, street, zip) values ";

    $valuesArr = array();
        foreach($newdata as $data){
            $id = $data['id'];
            $name = $data['eventname'];
            $start = $data['eventstart'];
            $end = $data['eventend'];
            $coverid = $data['coverid'];
            $coverurl = $data['coverurl'];
            $placeid = $data['placeid'];
            $placename = $data['placename'];
            $city = $data['city'];
            $country = $data['country'];
            $latitude = $data['latitude'];
            $longitude = $data['longitude'];
            $street = $data['street'];
            $zip = $data['zip'];

            $name = mysqli_real_escape_string($conn, $name);

            $valuesArr[] = "('$id', '$name', '$start', '$end', '$coverid', '$coverurl', '$placeid', '$placename', '$city', '$country','$latitude','$longitude','$street','$zip')";
        }
    $sql .= implode(',', $valuesArr);
    $result = mysqli_query($conn,$sql);
    if(!$result)
    {
        die('Error : ' . mysqli_error($conn));
    }
}

我想忽略已经存在的条目，然后继续下一行。

最佳答案

=>尝试使用此方法检查电子邮件ID，您可以使用此方法验证所有已归档

$query = mysqli_query($con, "SELECT * FROM emails WHERE email='".$email."'");

if(mysqli_num_rows($query) > 0){

    echo "email already exists";
}else{
    // do something
    if (!mysqli_query($con,$query))
    {
        die('Error: ' . mysqli_error($con));
    }
}

关于php - PHP:检查mysql中是否存在行，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/44779921/

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Answer 1

=>尝试使用此方法检查电子邮件ID，您可以使用此方法验证所有已归档

$query = mysqli_query($con, "SELECT * FROM emails WHERE email='".$email."'");

if(mysqli_num_rows($query) > 0){

    echo "email already exists";
}else{
    // do something
    if (!mysqli_query($con,$query))
    {
        die('Error: ' . mysqli_error($con));
    }
}