How do I use T-SQL Group By

Question

I know I need to have (although I don\'t know why) a GROUP BY clause on the end of a SQL query that uses any aggregate functions like count,

Answer 1

Counting the number of times tags are used might be a google example:

SELECT TagName, Count(*)
AS TimesUsed
FROM Tags
GROUP BY TagName ORDER TimesUsed

If you simply want a distinct value of tags, I would prefer to use the DISTINCT statement.

SELECT DISTINCT TagName
FROM Tags
ORDER BY TagName ASC