If you’re looking for an even quicker way to write your GROUP BY clauses, you can use the column’s index instead of its name.

For example, in our previous query, where we used GROUP BY to calculate the average salary for each department in the employees table, the column department is the first column in our SELECT clause. As a result, instead of writing the column name “department” in our GROUP BY clause like this:

SELECT
  department,
  AVG(salary) AS avg_salary
FROM employees
GROUP BY department

we can simply reference the department column’s index in our SELECT clause. In this case, because the department column is the first column to be mentioned in our query, we’d use the index 1, and write the following:

SELECT
  department,
  AVG(salary) AS avg_salary
FROM employees
GROUP BY 1

This would give the same results as the previous query.