如何在SQL中解析以逗号分隔的字符串变量

I am working in SQL Server 2008. I have a stored proc that takes a parameter, called @test. This parameter is varchar(255). In this stored proc, I need to parse this string, convert each value into a string itself (there will be a variable number of values), and build a list to use in a NOT IN statement.I am working in SQL Server 2008. I have a store