I think you are trying to use MID as function.
If this is true, there are couple of problems I assume.
1. MID is function to find a substring from a coulmn. The way you have used doesn't seem right. The syntax for MID is
SELECT MID(column_name,start[,length]) FROM table_name
2. MID I think is not available in SQL 2008. It was/is there in Access. You can use substring method in SQL 2008. The syntax for the substring is same
SELECT substring(column_name,start[,length]) FROM table_name
In both cases length is an optional parameter.
Hope that helps