Skip to main content
Practice

COUNT and SUM

Two of the most useful SQL tools for summarizing data are COUNT() and SUM().
They help you answer questions like:

  • How many orders were placed?
  • What's the total amount spent?

COUNT: How Many Rows?​

COUNT() is used to count rows in a table.

Count total clients
SELECT COUNT(*) 
FROM clients;

This returns the total number of rows in the clients table.

To count only non-null values in a column, you can use the COUNT() function with a column name.

Count clients with email
SELECT COUNT(email)
FROM clients;

SUM: Add Up Values​

SUM() adds together values from a numeric column.

Total sales
SELECT SUM(order_total)
FROM client_orders;

This returns the total amount spent across all orders.

Note: Works only with numeric types like INT or REAL.

Want to learn more?

Join CodeFriends Plus membership or enroll in a course to start your journey.