EasySQL challenge #39WHERE

Recent Employees

Find employees hired after 2020.

The challenge runs on the SQLabHub practice database (SQLite) and uses the employees table. You can solve it in the browser, with nothing to install.

Solve This SQL Challenge

The task

Find employees hired after 2020.

A correct answer returns 62 rows with 12 columns: id, first_name, last_name, email, department, department_id, title, salary, hire_date, manager_id, city, status.

Tables used in this challenge

`employees` 120 rows

id INTEGER (PK) · first_name TEXT · last_name TEXT · email TEXT · department TEXT · department_id INTEGER · title TEXT · salary REAL · hire_date TEXT · manager_id INTEGER · city TEXT · status TEXT

First 3 rows of the employees table
id	first_name	last_name	email	department	department_id	title	salary	hire_date	manager_id	city	status
1	William	Lewis	wlewis18@corp.io	Customer Success	7	Senior CS Manager	61774	2022-07-24	NULL	San Diego	active
2	John	Miller	jmiller51@corp.io	Legal	8	Paralegal	191694	2021-08-09	NULL	San Diego	active
3	Daniel	Rivera	drivera50@corp.io	Engineering	1	VP Engineering	135067	2016-06-06	NULL	Houston	active

The first rows of each table are shown. See how all the tables relate on the database schema page.

Expected output

Expected output of the challenge
id	first_name	last_name	email	department	department_id	title	salary	hire_date	manager_id	city	status
1	William	Lewis	wlewis18@corp.io	Customer Success	7	Senior CS Manager	61774	2022-07-24	NULL	San Diego	active
2	John	Miller	jmiller51@corp.io	Legal	8	Paralegal	191694	2021-08-09	NULL	San Diego	active
4	Melissa	Smith	msmith33@corp.io	Engineering	1	VP Engineering	51465	2022-04-13	NULL	Fort Worth	active
6	Amy	Nguyen	anguyen90@corp.io	Design	10	Product Designer	194543	2021-01-16	NULL	Seattle	on_leave
7	Barbara	Rivera	brivera5@corp.io	HR	4	Recruiter	92575	2020-05-14	NULL	Jacksonville	active

First 5 of 62 rows. This is the output of the model solution on the practice database. The task does not fix a sort order, so your rows may come back in a different order.

What you practise

Returning every column of a table with SELECT *
Filtering rows with a WHERE condition

Hint and approach

Try the challenge first. Open these only when you need them.

Show the hint

Use hire_date

Show the step-by-step approach

How the model solution is built, in the order the database evaluates it:

Read from the employees table.
Filter in WHERE: keep the rows where hire_date is greater than '2020-01-01'.
Return every column with SELECT *.

Model solution

Checking your session…

What to watch for

WHERE. WHERE is evaluated before the SELECT list, so it cannot use a column alias defined there or the result of an aggregate.
SELECT *. SELECT * is fine for exploring, but its output changes whenever a column is added to the table. Queries that feed a report should name their columns.