1. SQL Recipes
2. Smoothing Data
3. Calculating Running Total

Calculating Running Total in SQL

While it's easy enough to compute the total of selected rows, it's far more interesting to compute a running total over time. A running total is the summation of a sequence of numbers which is updated each time a number is added to the sequence, by adding the value of the new number to the previous running total.

For example, if your dataset is a "users_joined" table like so:

You can compute the total number of users joined in a day like this:

select date, count(user_id) from users_joined 
group by date order by date;

Which will give you a result like this:

If you wanted to compute a running total (or cumulative sum) of the counts, you can use a SQL window function to achieve that:

select date,
       count(user_id) as count,
       sum(count(user_id)) over (order by date) as running_total
from users_joined
group by date
order by date;