Add record using mysql service with php

$userDetailsData = ['provider_type' => ($payload['provider_type']),
'provider_user_id' => ($payload['provider_user_id']),
'user_id' => ($userProfileGetCall['content']['id'])];

$userDetailsPostCall = $post("mysql/_table/user_details",$userDetailsData);

an example from my code. Also see what the log file in apps/dreamfactory/htdocs/storage/logs shows after you run your script.