SQL GROUP BY

Jun 5, 2023

Used in collaboration with aggregate functions like COUNT(), SUM(), AVG(), MAX(), or MIN(). It arranges the result set into groups based on the values of specified columns.

If you’re going to do any grouping / aggregation at all, then you must only SELECT grouped / aggregated columns.

• Multiple Group By: Need multiple columns to be the same.

Like WHERE but for GROUP BY

• sql - Using group by on multiple columns - Stack Overflow
• sql - GROUP BY without aggregate function - Stack Overflow