Date Picker Filter variable from and To

I have Query in grafana postgres data source like

Select ID , Name , description from Employ where id =$employID and joiningdate between fromdate and todate

if I want to achieve this using variable and date picker how I will write the query in grafna for Postgres data source. I know how to use a variables but I am not sure how from and to date which is selected as a rang can be used as a filter in a query.

what is the grafana system variable for date picker from and to date