GROUP BY

Like distinct in that it will get all unique sets of rows that are included in the select.

All columns in the select must be in the group by, except for aggregates.

Basic

SELECT colName
FROM SchameName.TableName
	GROUP BY colName

Two columns

SELECT colName, colName2
FROM SchameName.TableName
	GROUP BY colName, colName2 -- colName2 must be included here or you will get an error

With Aggregates

Count of the number of rows for each unique colName value

SELECT 
	colName,
	COUNT(*)
FROM SchemaName.TableName
	GROUP BY colName