SQL GROUP BY Guide - Essential SQL

Group By in SQL Server with CUBE, ROLLUP and GROUPING SETS Examples

GROUP BY SQL Queries to Summarize and Rollup Sets of Records

Number of records in a table with different conditions by using SQL count() in less than 2 minutes

SQL COUNT Code Examples

2 Ways to Calculate Distinct Count with Pivot Tables - Excel Campus

Overview of SQL RANK functions

SQL PARTITION BY Clause overview