No data for my pie chart

Hello, I am a beginner on Grafana.

I have to make a pie chart.

My data source is a SimpleJson and when I click on Save & test, I get “Data source is working”.

Here is my php backend file:

header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Headers: accept, content-type');
header('Access-Control-Allow-Methods: POST');
header('Content-Type: application/json');


switch ($uri) {
    case '/':

    case '/search':
        echo json_encode(["Browser","Revenue"]);

    case '/query':
        $responseQuery = [
            "columns" => [
                ['text' => 'Browser', 'type' => 'string'],
                ['text' => 'Revenue', 'type' => 'number']
            "rows" => [
                ['Chrome', 78952],
                ['Edge', 43256],
                ['Firefox', 20365]
            "type" => "table"
        echo json_encode($responseQuery);

    case '/annotations':
        echo "requete annotations";

        echo "requete non prise en charge";

In the grafana interface, I choose “Add a new panel” and visualization: pie chart.

I click on “+Query” and choose “table” and metric: “Revenue”.

My problem is that I always see “No data” displayed.

Can you please help me to achieve my goal?

Sorry for my English.

Thank you

hav you selected the simplejson datasource in the query editor? Can you interact with your JSON endpoint using cURL? If so, what query are you using?