You'll have to query the system tables (if supported for the type of database). Go to File>Options>Database tab, and check the box next to 'System Tables'.
For example, if your database is MSSQL Server, you would add the syscolumns and sysobjects tables, join on so.id = sc.id, and your record selection formula would be:
{syscolumns.name} = "ClientID"
-dave