SQL Server 2005:charindex starting from the end

Question

I have a string \'some.file.name\',I want to grab \'some.file\'.

To do that,I need to find the last occurrence of \'.\' in a string.

My solution is :

Answer 1

Here is a shorter version

DECLARE @someStr varchar(20)
set @someStr = '001.002.003'

SELECT REVERSE(Substring(REVERSE(@someStr),CHARINDEX('.', REVERSE(@someStr))+1,20))