在插入之前检查重复项 [英] Check for duplicates before inserting

问题描述

在插入数据库之前，我使用以下代码来检查重复项。对于我来说，当 name ， description ， price ， city 和 enddate match。

Before inserting into the database, I'm using the following code to check for duplicates. To me, a duplicate is only considered a duplicate when 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)
        ....

在运行此检查之前定义每个值，我的结果总是随着项目已存在而返回，我转储了dupesql并将命令复制/粘贴到phpmyadmin中，返回计数0.

Each value is defined prior to running through this checking, my result always comes back as item already exists. I dumped "dupesql" and copy/pasted the command into phpmyadmin which comes back with count 0.

推荐答案

您要执行以下操作：

$dupesql = "SELECT * FROM table where (name = '$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($duberaw) > 0) {
  //your code ...
}

请参阅此处了解更多信息

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