插入前检查是否有重复项

在插入数据库之前，我使用以下代码来检查重复项。对我来说，只有在以下情况下重复才被视为重复：name, description, price, city, and enddate match.

foreach($states_to_add as $item) {
    $dupesql = "SELECT 
                    COUNT(*) 
                FROM 
                    table 
                WHERE 
                    (   
                        name = '$name' 
                        AND description = '$description' 
                        AND manufacturer = '$manufacturer' 
                        AND city ='$city' 
                        AND price = '$price' 
                        AND enddate = '$end_date'
                    )";

    $duperaw = mysql_query($dupesql);

    if($duperaw > 0) {
        echo nl2br("$name already exists in $city \n");
    } 
    else {
        $sql = "INSERT INTO table (..... (here go the values to be inserted)
        ....

每个值都是在运行此检查之前定义的，我的结果总是因为项目已经存在而返回。我转储了“dupesql”并将命令复制/粘贴到 phpmyadmin 中，该命令返回的计数为 0。

您想要执行以下操作：

$dupesql = "SELECT * FROM table where (name = '$name' AND description = '$description' AND manufacturer = '$manufacturer' AND city ='$city' AND price = '$price' AND enddate = '$end_date')";

$duperaw = mysql_query($dupesql);

if (mysql_num_rows($duperaw) > 0) {
  //your code ...
}

See Here http://php.net/manual/en/function.mysql-num-rows.php了解更多信息。