HardSQL challenge #231WINDOW FUNCTIONRUNNING TOTALANALYTICS

Running Salary Total

Running total of salary by hire date.

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

Running total of salary by hire date.

A correct answer returns 120 rows with 2 columns: hire_date, running_total.

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
hire_date	running_total
2015-01-14	204449
2015-02-16	370737
2015-02-26	522891
2015-03-19	726358
2015-04-24	807703

First 5 of 120 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

Accumulating a value row by row with an ordered window

Hint and approach

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

Show the hint

SUM OVER

Show the step-by-step approach

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

Read from the employees table.
Compute SUM(salary) as a running window function: it covers the rows from the start up to the current one, ordered by hire_date.

Model solution

Checking your session…

What to watch for

Running totals. With ORDER BY and no frame, rows that tie on the sort column are added together in one step. Use ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW for a strict row-by-row total.