1. Please write a stored function named fHw2 1 xxxx based on the Staff table. It should take one argument branchno and it should meet the following 2 test cases. 10 points) If the given branchno (10 points) If the given branchno is 1B 1A. in the Staff table, please return the average salary of is not in the Staff table, please return a NULL value. the staff with the given branchno mysql select fHW2 1 XXXX(B009') as output; l output I l output I NULL 18000 l