Selecting Expressions That Use Arithmetic Operators
You can combine numeric expressions with arithmetic operators to
make complex expressions. You cannot combine expressions that contain
aggregate functions with column expressions. These examples show expressions
that use arithmetic operators within a select list in the Projection
clause:
SELECT stock_num, quantity*total_price FROM customer; SELECT price*2 doubleprice FROM items; SELECT count(*)+2 FROM customer; SELECT count(*)+LENGTH('ab') FROM customer;