Why computed values add flexibility in MySQL - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select the total price by multiplying quantity and price_per_unit.

MySQL

SELECT quantity * [1] AS total_price FROM orders;

Drag options to blanks, or click blank then click option'

Aprice_per_unit

Btotal

Cprice

Dcost

Attempts:

3 left

💡 Hint

Common Mistakes

Using a column name that does not exist in the table.

Forgetting to multiply quantity by the unit price.

The column price_per_unit holds the unit price. Multiplying it by quantity gives the total price.

2fill in blank

medium

Complete the code to calculate the discount amount by multiplying price and discount_rate.

MySQL

SELECT price * [1] AS discount_amount FROM products;

Drag options to blanks, or click blank then click option'

Arate

Bdiscount

Cdiscount_rate

Ddiscount_percent

Attempts:

3 left

💡 Hint

Common Mistakes

Using a column that does not represent the discount rate.

Confusing discount amount with discount rate.

The discount_rate column holds the rate to calculate the discount. Multiplying it by price gives the discount amount.

3fill in blank

hard

Fix the error in the code to compute the total cost including tax.

MySQL

SELECT price * quantity + price * quantity * [1] AS total_cost FROM sales;

Drag options to blanks, or click blank then click option'

Atax_rate

Btax

Ctaxamount

Drate

Attempts:

3 left

💡 Hint

Common Mistakes

Using a column that does not represent the tax rate.

Forgetting to multiply tax rate by the total price.

The tax_rate column holds the tax percentage. Multiplying it by the total price (price * quantity) adds the tax amount.

4fill in blank

hard

Fill both blanks to calculate the final price after discount.

MySQL

SELECT price * [1] AS discount_amount, price - [2] AS final_price FROM items;

Drag options to blanks, or click blank then click option'

Adiscount_rate

Bdiscount_amount

Cdiscount

Drate

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up discount rate and discount amount.

Using the same column for both blanks.

The first blank uses discount_rate to calculate the discount amount. The second blank uses discount_amount to subtract from price for the final price.

5fill in blank

hard

Fill all three blanks to compute total cost including tax and discount.

MySQL

SELECT price * quantity AS subtotal, subtotal * [1] AS tax_amount, subtotal - subtotal * [2] + [3] AS total_cost FROM orders;

Drag options to blanks, or click blank then click option'

Atax_rate

Bdiscount_rate

Ctax_amount

Ddiscount_amount

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing tax and discount columns.

Using discount amount before calculating it.

The first blank is tax_rate to calculate tax amount from subtotal. The second blank is discount_rate to calculate discount from subtotal. The third blank is tax_amount to add tax back after discount.