SQL Server Fast Row Count function

FastCount.sql

if object_id('dbo.FastCount', 'FN') is not null
begin
	drop function dbo.FastCount	
end
go
create function dbo.FastCount(@object_id int)
returns bigint
as
begin
	declare @fastcount bigint = 0

	select 	@fastcount = sum (p.rows)
	from 	sys.tables as t
	inner 	join sys.partitions as p on p.object_id = t.object_id
	where	p.index_id < 2
	and		t.object_id = @object_id 

	return	@fastcount
end