To evaluate the SQL statement and understand the impact of removing parentheses from the calculation, let's break down the statement and analyze each part:
The SQL statement is as follows:
SELECT e.employee_id, (.15 * e.salary) + (.5 * e.commission_pct) + (s.sales_amount * (.35 * e.bonus)) AS CALC_VALUE
FROM employees e, sales s
WHERE e.employee_id = s.emp_id;
The statement selects the employee ID (e.employee_id) and calculates the value in the CALC_VALUE column. The calculation involves multiple mathematical operations, including multiplication and addition.
If we remove all the parentheses from the calculation, the statement would look like this:
SELECT e.employee_id, .15 * e.salary + .5 * e.commission_pct + s.sales_amount * .35 * e.bonus AS CALC_VALUE
FROM employees e, sales s
WHERE e.employee_id = s.emp_id;
Now, let's compare both versions of the SQL statement.
The original version of the statement uses parentheses to group certain parts of the calculation, which ensures that these parts are evaluated together before performing the addition operation. Removing the parentheses means that the calculation will be evaluated based on the order of operations (PEMDAS/BODMAS), where multiplication is performed before addition.
However, since the multiplication and addition operations are being performed on constants and column values, the order of operations does not affect the final result. The multiplication and addition operations are commutative, which means the order in which they are performed does not change the result.
Therefore, removing the parentheses from the calculation will not make any difference in the value displayed in the CALC_VALUE column. Hence, the correct answer is C) There will be no difference in the value displayed in the CALC_VALUE column.