Write an SQL query for the following: For each customer, find the busiest date (year, month, day) and slowest date -- i.e., made the most/least numbers of sales transactions (i.e., maximum/minimum counts of sales transactions, not maximum/minimum quantities)

sales (prod, cust, yr, mo, day, state, quant)

cust busy_yr busy_mo busy_dy slow_yr slow_mo slow_dy

Sam 2020 6 27 2012 12 31

Mia 2017 11 17 2009 3 25

. . . . . . . . . . . . . . . . . . . . .

Emily 2011 9 23 2012 7 2