In this article, we will learn how to use the GROUP BY keyword in SQL.
The GROUP BY statement is used to group rows that have the same values.
The GROUP BY statement is usually used with Aggregate Functions to group the result-set by one or more columns.
SELECT column_name(s) FROM TABLE_NAME GROUP BY column_name(s);
The subsequent statement would list the number of viewers in each city:
SELECT COUNT(ID), City FROM Viewers GROUP BY City;
Also, check How To Use UNION Operator In SQL