How to plot a graph panel on Grafana Dashboard with MySQL datasource

I have a table on MySQL that contains id, task_name, process_date, start_time and finish_time. I want to generate a graph that show how many minutes take to execute each process. It just has one process per day. So, I wanna to show date on axis X and time in minutes on axis Y, and show the data in bars format. Like this:


I tested a query on database and worked well. The query that I built:

SELECT process_date as “date”, TIMEDIFF(finish_time, start_time) as “during” FROM test;

This query returned what I want:


But this query, as I expected, doesn’t work on Grafana. Does anyone have any idea how to do what I want?