Can you clarify your problem a little more? In most connection types (Oracel, SQL Server, Excel, etc) you can specify Custom SQL to tailor your connection. Or, once you've connected, with certain connections you can run "pass-through" SQL commands using the Calculated Field dialog box.
can i get all fields through SQL commands using passthrough sql functions directly from data base without tableau interpretetion.
if so what are the connections that i need to get to run ? or is there any command line interface to pass the commanda to tableau?