Group by

Group By Statement

The GROUP BY statement groups rows that have the same values into summary rows, like "find the number of commits for each username or email".

SELECT * FROM commits GROUP BY author_name
SELECT * FROM commits GROUP BY author_name, author_email
SELECT * FROM commits GROUP BY LEN(author_name)

You can use The ROLLUP feature to extends GROUP BY to include subtotals and grand totals in the result set.

SELECT COUNT() FROM commits GROUP BY author_name WITH ROLLUP