SQL - Select substring

[PhilEaton]

Hello!
I need to write a query that selects TableID (a previously concatenated string) and also selects a substring of TableID as another column. All data in TableID is in the format %System.Variable, %Class.User, etc. I need to select from the % to the '.' to return something like %System and %Class respectively. Any suggestions?
Thanks!
Phil

[PhilEaton]

Got it working!
substring(TableId,1,charindex('.',TableId)-1) AS Package,