php - 检查我的数据库表中是否存在某个值

Question

我想检查我的 MySQL 数据库表中是否存在 URL，例如 Url=exist、message=url 是否已存在

<?php
if(isset($_POST['Submit'])){
    $dbhost = 'localhost';
    $dbuser = '####';
    $dbpass = '#######';
    $conn = mysql_connect($dbhost, $dbuser, $dbpass);
    $Title = $_POST['Title'];
    $Url = $_POST['Url'];
    $email_data = $_POST['email_data'];
    $type_data = $_POST['type_data'];
    $sql = "INSERT INTO table ". "(Title,Url,email_data,type_data)"."VALUES('$Title','$Url','$email_data','$type_data')";
    mysql_select_db('dbname');
    $retval = mysql_query( $sql, $conn );
        if(! $retval ){
            die('Could not enter data: ' . mysql_error());
        }
    echo "<script type='text/javascript'>alert('submitted successfully!')</script>";
    mysql_close($conn);
} else {
?>

Answer 1

你可以这样做

$sql = "SELECT Url FROM 'your_table_name' WHERE Url = $_POST['Url']";

运行这个sql，如果它返回true，你就可以说它存在。