SQL exercises with solutions: SELECT, aliases and DISTINCT

Updated on 22 September 2026

SELECT picks the columns to show; AS renames a column, DISTINCT removes duplicates. These 4 exercises range from level 1 to level 1; they use the syntax of SQLite, SpeedQL’s SQL engine.

Tip: List the columns you need rather than SELECT *: the result is easier to read and faster.

Read the “SELECT, aliases, DISTINCT” card in the cheat sheet

Exercise 1 · level 1

Show every column and every row of the employees table.

Table `employees` (4 rows)
id	name	department	salary
1	Alice	Finance	32000
2	Bob	IT	41000
3	Claire	Finance	38000
4	David	HR	29000

Show the hint

Topics to use: SELECT, aliases, DISTINCT.

Query structure:

SELECT *
FROM …

Show the solution

SELECT *
FROM employees;

Expected result (4 rows):

id	name	department	salary
1	Alice	Finance	32000
2	Bob	IT	41000
3	Claire	Finance	38000
4	David	HR	29000

Exercise 2 · level 1

Show only the name and the salary of every employee.

Table `employees` (4 rows)
id	name	department	salary
1	Alice	Finance	32000
2	Bob	IT	41000
3	Claire	Finance	38000
4	David	HR	29000

Show the hint

Topics to use: SELECT, aliases, DISTINCT.

Query structure:

SELECT …, …
FROM …

Show the solution

SELECT name, salary
FROM employees;

Expected result (4 rows):

name	salary
Alice	32000
Bob	41000
Claire	38000
David	29000

Exercise 3 · level 1

Show the employees' names in a column called employee, and their salaries in a column called annual_salary.

Table `employees` (4 rows)
id	name	department	salary
1	Alice	Finance	32000
2	Bob	IT	41000
3	Claire	Finance	38000
4	David	HR	29000

Show the hint

Topics to use: SELECT, aliases, DISTINCT.

Query structure:

SELECT … AS …, … AS …
FROM …

Show the solution

SELECT name AS employee, salary AS annual_salary
FROM employees;

Expected result (4 rows):

employee	annual_salary
Alice	32000
Bob	41000
Claire	38000
David	29000

Exercise 4 · level 1

Show the list of product categories, without duplicates.

Table `products` (6 rows)
id	name	category	price	stock
1	Keyboard	Office	25	40
2	Mouse	Office	15	0
3	Screen	Display	180	12
4	Headset	Audio	60	8
5	Webcam	Office	45	0
6	Speaker	Audio	35	25

Show the hint

Topics to use: SELECT, aliases, DISTINCT.

Query structure:

SELECT DISTINCT …
FROM …

Show the solution

SELECT DISTINCT category
FROM products;

Expected result (3 rows):

category
Office
Display
Audio

Practice with automatic checking

In SpeedQL, you write your query and it is checked straight away, on these tables and then on a hidden dataset.

Practice on the 4 “SELECT, aliases, DISTINCT” questions