Alias in where clause

Question

Hi,
This is a OCA certification question.
1. SQL> SELECT prod_name,prod_list_price,prod_list_price-(prod_list_price*.25) "DISCOUNTED_PRICE"
FROM products
WHERE discounted_price<10;
The query generates an error.
What is the reason of generating error?
A. The parenthesis should be added to enclose the entire expression
B. The double quotation marks should be removed from the column alias
C. The column alias should be replaced with the expression in the WHERE clause
D. The column alias should be put in uppercase and enclosed within double quotation marks in the WHERE clause
Answer: D
My question is how can we use alias ("DISCOUNTED_PRICE") in where clause as (WHERE "DISCOUNTED_PRICE"<10) ??
please clarify.

Answer 1

Hi,
Answer C. (and I beleive, you are not writing the exam right now )
You cant use alias name in WHERE clause.
And if you still want to use DISCOUNTED_PRICE in WHERE clause, you need to use inline view.
SELECT *
FROM (SELECT prod_name,prod_list_price,prod_list_price-(prod_list_price*.25) "DISCOUNTED_PRICE"
FROM products
WHERE  WHERE discounted_price<10;Cheers,
Suri