This question is for SQL$.$

I apologise, i do not have a test database to upload for this question. What i need help with is for an SQL statement that always pulls data going back a year from the present day. The statement will pull and list the total amount of time a given variable is in a specific state. For example if a database had a list of car models, and each model had a number of states that car could be in$,$ Ex$.($Running$,$ Scheduled$-$Maint, Unscheduled$-$Maint, Scrapped$).$ The statement will need to pull out the total time each model is spent in the Unscheduled$-$Maint state that year. The statement will also need to pull out and combine the total amount of time each car model is spent in the other states that year.