SQL data types

1

Is there a way to see every data type that has been used in a database? if so, how do I do it?

2

Something like this:

SELECT 
	DISTINCT t.name
FROM
	sys.objects o
	INNER JOIN sys.columns c ON
		c.object_id = o.object_id
	INNER JOIN sys.types t ON 
		t.system_type_id = c.system_type_id
WHERE
	o.type IN ('U')

The sys.columns table lists all the columns in your tables. The query is trying to pick up only columns from user-defined tables from those. You may need to expand it/modify it depending on your requirements.