yii2如何获得选定的下拉值

Question

I am trying to do a Yii2 application.

I have 'customerID', 'customerName' and 'total' column in mysql.

I want to show user to selected customers's total value to user.

For Example.

Customer 1 = 100
Customer 2 = 250
Customer 3 = 300
Customer 1 = 300
Customer 3 = 500

So. If user choose Customer 3 in my dropdownlist I want to show user to 300+ 500 = 800.

I can see the sum of total columns for specific customer. But I cant get the sum of total columns of selected customer

How can I do this?

This is my code below.

<?php $form = ActiveForm::begin(); ?>
<?php $chosen = ""; ?>

<?= $form->field($model, 'customerName')->dropDownList(
    ArrayHelper::map(Siparisler::find()
        ->all(),'customerName','customerName'),
    [
    'prompt'=>'Chose a Customer'
    ]

    );



$var    = ArrayHelper::map(Siparisler::find()->where("(customerName = '$chosen' )")->all(),'total','total');

echo "<h3><br>"."Total"."<br><h3>";


$sum = 0;
foreach($var as $key=>$value)
{
   $sum+= $value;
}
echo $sum;

?>

Answer 1

try this. These should be in your controller's action

public function actionTotal() {

    //you've use $chosen for selected customer in drop down list
    $chosen = Yii::$app->request->post('chosen', '');

    // select all customer data based on $chosen
    $customers = Siparisler::find()->where(['=', 'customerName', $chosen])
                               ->all();

    $sum = 0;
    foreach($customers as $k=>$customer)
    {
        $sum += $customer->total;
    }

    return $this->render('total', [
        'sum' => $sum,
        'customers' => $customers,
    ]);
}

these code below should be your view

$form = ActiveForm::begin();

// i use yii\helpers\Html
Html::dropDownList('chosen', ArrayHelper::map(Siparisler::find()->all(), 'customerName', 'customerName'),
                    [
                        'prompt'=>'Chose a Customer'
                    ]);
Html::submitButton('Submit');

ActiveForm::end();

 echo "<h3><br>" . "Total" . "<br>" . $sum . "<h3>";

Answer 2

In addition to David's answer: Summing over a column can also be done in pure SQL. This might save you from some unwanted PHP complexity (I try to avoid ArrayHelper::map whenever I can). The query for this would be

SELECT
  sum(total) as sumTotal
FROM customer
WHERE customerName = '<NAME>';

or in Yii2:

Siparisler::find()->where(['customerName' => $chosenName])->sum('total');