php - 如何在 mysql php 中更新多选下拉数组

Question

我在我的项目中使用多选下拉菜单。现在我想更新 mysql 数据库中的多选下拉数组值。我成功在数据库中添加了多选值，但是当我尝试更新时，我得到了错误的结果。例如，如果数组中的值类似于 Array([0]=>A [1]=>B) 并且我运行循环来更新数据库中的值，则更新后的值始终为第二个值数组(例如[1]=>B)。我不知道问题出在哪里请帮忙..下面是我的代码..

HTML

<select name="countries[]" id="countries" multiple="multiple" placeholder="Which countries did you sell your products in *" required>
<option value="" disabled="disabled" selected>Which countries did you sell your products in *</option>
<option value="Afghanistan">Afghanistan</option>
<option value="Albania">Albania</option>
<option value="Algeria">Algeria</option>
<option value="American Samoa">American Samoa</option>
<option value="Andorra">Andorra</option>
<option value="Angola">Angola</option>
<option value="Anguilla">Anguilla</option> 

PHP

$countries = $_POST['countries'];
$user_id = $_SESSION['user_session'];
$size=sizeof($countries);
for($i=0;$i<$size;){
    $count = $trade_info->update_supplier_last_financial_count($user_id, $countries[$i]);
    $i++;
}

函数 (update_supplier_last_financial)

public function update_supplier_last_financial_count($user_id,$last_count){

    $db = db::getInstance();    
    $pdo = $db->getConnection();

    try {
        $stmt = $pdo->prepare("UPDATE supplier_last_financial_countries SET countries = :last_count WHERE user_id = :user_id ");

        $stmt->bindparam(":user_id", $user_id);
        $stmt->bindparam(":last_count", $last_count);

        $stmt->execute();

        return $stmt;   
    }

    catch(PDOException $e) {
        echo $e->getMessage();
    }

}

提前致谢..

Answer 1

您的查询正在一遍又一遍地更新同一行。它受到 WHERE 的限制，但 WHERE ($user_id) 的条件永远不会改变。

像这样的东西可能会起作用:

$countries = $_POST['countries'];
$user_id = $_SESSION['user_session'];
foreach ($countries as $country) {
    $count = $trade_info->update_supplier_last_financial_count($user_id, $country);
}

public function update_supplier_last_financial_count($user_id,$last_count) {
    $db = db::getInstance();    
    $pdo = $db->getConnection();

    try {
        $stmt = $pdo->prepare("DELETE FROM supplier_last_financial_countries WHERE user_id = :user_id ");
        $stmt->bindparam(":user_id", $user_id);
        $stmt->execute();

        $stmt = $pdo->prepare("INSERT INTO supplier_last_financial_countries SET countries = :last_count, user_id = :user_id ");
        $stmt->bindparam(":user_id", $user_id);
        $stmt->bindparam(":last_count", $last_count);
        $stmt->execute();

        return $stmt;   
    } catch(PDOException $e) {
        echo $e->getMessage();
    }
}