If you want to find out which user agents are used to visit your site, you can use the below query. You can use this to find out about browsers, and honest-ish robots (i.e. ones that identify themselves via the user agent).
SELECT cs(User-Agent), count(cs(User-Agent)) as requestcount FROM '[LOGFILEPATH]' WHERE date = '2016-08-02' GROUP BY cs(User-Agent) ORDER BY count(cs(User-Agent)) DESC
Remember to change the date when you run it.
Web Log Importer
If you are using Web Log Importer, you can get the same information using the following query:
SELECT [cs_user_agent], COUNT(1) as RequestCount FROM LogEntry WHERE [date] = '2020-03-10' GROUP BY [cs_user_agent] ORDER BY COUNT(1) DESC