Relational database basics in Intro to Computing - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select all columns from the table named 'students'.

Intro to Computing

SELECT [1] FROM students;

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

Aeverything

B*

Ccolumns

Dall

Attempts:

3 left

💡 Hint

Common Mistakes

Using words like 'all' or 'columns' instead of the symbol *.

Leaving the blank empty.

In SQL, * means select all columns from the table.

2fill in blank

medium

Complete the code to filter records where the age is greater than 18.

Intro to Computing

SELECT * FROM users WHERE age [1] 18;

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

A>

B=

C<

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' which means exactly equal.

Using '<' which means less than.

The symbol > means 'greater than' in SQL conditions.

3fill in blank

hard

Fix the error in the SQL statement to count the number of rows in the 'orders' table.

Intro to Computing

SELECT COUNT([1]) FROM orders;

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

Aorder_id

Brows

Call

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using words like 'all' or 'rows' which are not valid in COUNT.

Using a column name that might have NULL values.

Using COUNT(*) counts all rows in the table.

4fill in blank

hard

Fill both blanks to create a table named 'employees' with columns 'id' as integer and 'name' as text.

Intro to Computing

CREATE TABLE employees (id [1], name [2]);

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

AINTEGER

BVARCHAR

CTEXT

DNUMBER

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'NUMBER' which is not standard SQL type here.

Using 'VARCHAR' without specifying length.

INTEGER is used for whole numbers, and TEXT is used for text strings in SQL.

5fill in blank

hard

Fill all three blanks to select 'name' and 'age' from 'people' where 'age' is less than 30.

Intro to Computing

SELECT [1], [2] FROM people WHERE [3] < 30;

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

Aname

Bage

Dperson

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'person' which is not a column name.

Mixing up the order of columns.

You select the columns name and age, and filter where age is less than 30.