Please Help me out of this

Question

Write a stored procedure to retrieve the sum of sales data based on passing parameter values,

1.if we pass the only year, it should provide a sum of sales of that year

2.if we pass year and month value, then we need to get the sum of sales of that month.

3.if we pass the year, month, week it should provide a sum of sales for that week only.

4.if we don't pass any value, it should provide an overall sum of sales of all years,