Cannot use auto scaling since it's impossible to determine a valid min/max value of the Y-axis in PHP

Question

I get this error when I execute my PHP code through the localhost. I used jpgraph library to plot. It's connected to my always data database and the error says:

It cannot use auto-scaling since it's impossible to determine a valid min/max value of the Y-axis (only NULL values).

Here is my PHP code

<?php // content="text/plain; charset=utf-8"
require_once('connectDBalwaysdata.inc.php');
require_once ('jpgraph/jpgraph.php');
require_once ('jpgraph/jpgraph_bar.php');


$query = "SELECT * FROM `transactions`;";
$result = mysqli_query($link,$query);

$nums = [];
$categories = [];
$num_of_used = array_fill(0,15,0);


while ( $row = mysqli_fetch_assoc($result) ){
    $IdCategory         = $row['idCategory'];
    $query_category     = "SELECT category FROM `categories` WHERE idCategory='{$IdCategory}'";
    $result_category    = mysqli_query($link, $query_category);
    $data_category      = mysqli_fetch_assoc($result_category);

    array_push($categories,$data_category['category']);
    $num_of_used[ $row['idCategory']-1 ]++;
    array_push($nums,$num_of_used);
}


$graph = new Graph(500,300,'auto');
$graph->SetScale("textlin");

$theme_class = new UniversalTheme;
$graph->SetTheme($theme_class);

$graph->yaxis->SetTickPositions(array(0,10,20,30,40,50,60),array(5,15,25,35,45,55));
$graph->SetBox(false);


$graph->ygrid->SetFill(false);
$graph->xaxis->SetTickLabels($categories);
$graph->yaxis->HideLine(false);
$graph->yaxis->HideTicks(false,false);


$b1plot = new BarPlot($nums);


$graph->Add($b1plot);


$b1plot->SetColor("white");
$b1plot->SetWidth(45);
$graph->title->Set("Categories of Transactions");


$graph->Stroke();

?>

Answer 1

Same issue happened to me, try this on your call to SetScale()

$graph->SetScale("textlin",0,65);

Obviously you could use different range values but the key for me was defining 0