Php Json Get Keys

I echoed this and fetched in ajax .

$result= $this->mpesa->STKPushQuery($checkoutRequestID, 174379, "bfb279f9aa9bdbcf158e97dd71a467cd2e0c893059b10f78e6b72ada1ed2c919");

The results am getting in json is:

{"requestId":"","errorCode":"400.002.02","errorMessage":"Bad Request - Invalid CheckoutRequestID"}

Now in my php code I need to get the Keys of errorCode that sometimes is a successCode so when I try this:

if ($result->errorCode=="400.002.02"){
    $Data = '{"status":"Submit payment before Checking for it"}';
    echo $Data;

Its fine because the errorCode is found in Json. When there is a success message i.e:

if ($result->successCode=="0"){
    $Data = '{"status":"Payment Successful"}';
    echo $Data;

}

I get an error with the first statement. Because errorCode is not found in Json So what I actually need is to get the key of json(which will be either errorCode or successCode) i.e

$mystatusCode== Get the either the errorCode or SuccessCode (key in Json array[1])
if ($results->mystatusCode=="400.002.02"){
        $Data = '{"status":"Submit payment before Checking for it"}';
        echo $Data;
}else if ($results->mystatusCode=="0"){
$Data = '{"status":"Payment has been processed successfully"}';
        echo $Data;
}

Answer

Using isset will accomplish your goal:

$mystatusCode = ( isset($result->errorCode) ? $result->errorCode : 
                    ( isset($result->successCode) ? $result->successCode : 
                        NULL
                    )
                );

Or you can just use it in the if statements directly without making a new single var:

if (isset($result->errorCode) && $result->errorCode == "400.002.02") {
    ...
}
elseif (isset($result->successCode) && $result->successCode == "0") {
    ...
}