Combining multiple aggregates in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to calculate the total number of orders.

SQL

SELECT COUNT([1]) FROM orders;

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

A*

Border_id

Ccustomer_id

Dorder_date

Attempts:

3 left

💡 Hint

Common Mistakes

Using COUNT(*) counts all rows but here we want to specify the column explicitly.

Using a column that can have null values may give incorrect counts.

The COUNT function counts non-null values in the specified column. Using order_id counts all orders.

2fill in blank

medium

Complete the code to find the average order amount.

SQL

SELECT AVG([1]) FROM orders;

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Aorder_amount

Border_date

Ccustomer_id

Dorder_id

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-numeric column causes errors.

Choosing the wrong column leads to meaningless results.

The AVG function calculates the average of numeric values in the specified column. Here, order_amount holds the amounts.

3fill in blank

hard

Fix the error in the code to get the maximum and minimum order amounts.

SQL

SELECT MAX(order_amount) AS max_amount, MIN([1]) AS min_amount FROM orders;

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

Acustomer_id

Border_id

Corder_date

Dorder_amount

Attempts:

3 left

💡 Hint

Common Mistakes

Using different columns for MAX and MIN causes inconsistent results.

Using non-numeric columns causes errors.

Both MAX and MIN should be applied to the same numeric column order_amount to get correct results.

4fill in blank

hard

Fill both blanks to calculate the total and average order amounts.

SQL

SELECT [1](order_amount) AS total, [2](order_amount) AS average FROM orders;

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

ASUM

BAVG

CCOUNT

DMAX

Attempts:

3 left

💡 Hint

Common Mistakes

Using COUNT instead of SUM for total.

Mixing up AVG and MAX functions.

SUM adds all order amounts to get the total. AVG calculates the average order amount.

5fill in blank

hard

Fill all three blanks to calculate the total orders, average amount, and maximum amount.

SQL

SELECT [1](order_id) AS total_orders, [2](order_amount) AS avg_amount, [3](order_amount) AS max_amount FROM orders;

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

ACOUNT

BAVG

CMAX

DMIN

Attempts:

3 left

💡 Hint

Common Mistakes

Using SUM instead of COUNT for total orders.

Using MIN instead of MAX for maximum amount.

COUNT counts total orders by order_id, AVG finds average order amount, and MAX finds the highest order amount.