Second Normal Form (2NF) in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the SQL query to select all columns from the table named 'Orders'.

SQL

SELECT [1] FROM Orders;

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

A*

BALL

CEVERYTHING

DCOLUMNS

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'ALL' instead of '*' to select all columns.

Using 'COLUMNS' or 'EVERYTHING' which are not valid SQL keywords.

The asterisk (*) is used in SQL to select all columns from a table.

2fill in blank

medium

Complete the SQL query to find orders where the quantity is greater than 10.

SQL

SELECT * FROM Orders WHERE quantity [1] 10;

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

A=

B<

C<=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' which checks for equality, not greater than.

Using '<' or '<=' which check for less than conditions.

The '>' operator is used to find values greater than a specified number.

3fill in blank

hard

Fix the error in the SQL query to select distinct customer IDs from Orders.

SQL

SELECT [1] customer_id FROM Orders;

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

ADISTINCT

BUNIQUE

CSINGLE

DONLY

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'UNIQUE' which is not valid in SELECT clauses for distinct values.

Using 'SINGLE' or 'ONLY' which are not SQL keywords.

The keyword 'DISTINCT' is used in SQL to return unique values.

4fill in blank

hard

Fill both blanks to create a SQL query that groups orders by customer_id and counts the number of orders.

SQL

SELECT customer_id, COUNT([1]) AS order_count FROM Orders GROUP BY [2];

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

A*

Border_id

Ccustomer_id

Dquantity

Attempts:

3 left

💡 Hint

Common Mistakes

Counting a specific column that might have NULLs instead of all rows.

Grouping by a column other than customer_id.

COUNT(*) counts all rows. GROUP BY customer_id groups the results by each customer.

5fill in blank

hard

Fill all three blanks to write a SQL query that selects product_id, sums quantity sold, and groups by product_id having total quantity greater than 100.

SQL

SELECT [1], SUM([2]) AS total_quantity FROM Sales GROUP BY [3] HAVING total_quantity > 100;

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

Aproduct_id

Bquantity

Dorder_id

Attempts:

3 left

💡 Hint

Common Mistakes

Grouping by order_id instead of product_id.

Summing a wrong column or not grouping properly.

Select product_id, sum the quantity sold, group by product_id to aggregate, and filter groups with total quantity over 100.