EasySQL challenge #97SUM

Total Payment Amount

Calculate total amount of all payments.

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

Solve This SQL Challenge

The task

Calculate total amount of all payments.

A correct answer returns 1 row with one column: SUM(amount).

Tables used in this challenge

`payments` 200 rows

id INTEGER (PK) · order_id INTEGER · user_id INTEGER · amount REAL · method TEXT · status TEXT · paid_at TEXT · transaction_id TEXT

First 3 rows of the payments table
id	order_id	user_id	amount	method	status	paid_at	transaction_id
1	46	105	921.62	Gift Card	success	2022-05-18	TXNHTN4GIK5L
2	157	37	1723.82	Bank Transfer	success	2024-11-11	TXNKJPIXJOFP
3	45	36	978.76	Bank Transfer	refunded	2023-10-24	TXNU2RW4MK1R

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
SUM(amount)
200873.37

The complete result: 1 row. This is the output of the model solution on the practice database.

What you practise

Summarising many rows into one value with COUNT, SUM, AVG, MIN or MAX

Hint and approach

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

Show the hint

SUM(amount)

Show the step-by-step approach

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

Read from the payments table.
Aggregate over all the rows that are left: compute SUM(amount). With no GROUP BY, the result is a single row.

Model solution

Checking your session…

What to watch for

Aggregate functions. Aggregates skip NULLs. AVG divides by the number of non-NULL values and COUNT(column) can be smaller than COUNT(*).