The customers table has the following structure: 
You need to write a query that does the following tasks:
1. Display the first name and tax amount of the customers. Tax is 5% of their credit limit.
2. Only those customers whose income level has a value should be considered.
3. Customers whose tax amount is null should not be considered.
Which statement accomplishes all the required tasks?
A.
Option A
B.
Option B
C.
Option C
D.
Option D
Explanation:
I think that the correct answer is “A”.
Certainly, the correct answer is “B”. No doubt.
I’m wrong.
A is wrong/. The correct answer is B because in option A, you cannot use alias in a where clause.
Exactly Mac. Thanks
Even option B is not fully correct… It should be (cust_credit_limit*.05) is NOT NULL.
If cust_credit_limit is NOT NULL. Than obviously (cust_credit_limit*0.5) is also NOT NULL.