Pivot Tables: GROUP BY + aggregate functions

Imagine This…

You run a small snack shop. At the end of each day, you record which employee sold what snack and for how much.

Your Sales Table (snack_sales)

Goal

You want to know: How much did each employee sell in total?

SQL Query

SELECT employee, SUM(amount) AS total_sales
FROM snack_sales
GROUP BY employee;
  

Expected Output

How It Works

• GROUP BY employee – SQL gathers all the rows for each employee.
• SUM(amount) – Adds up the sales amount for each group.
• AS total_sales – Assigns a label to the result column.

Other Useful Aggregates

Example: Average Sales per Employee

SELECT employee, AVG(amount) AS avg_sale
FROM snack_sales
GROUP BY employee;