this is not possible in QlikView. You can only load data from one connection per statement. A possible solution would be to load all Ticket_Num from SQL Server in a QlikView table and then for-loop over the table to execute single SQL selects on Teradata with the Ticket_Num in Where Clause.
// This is an example:
SQL SELECT Ticket_Num FROM SQLServer.dbo.Table;
LET rows = NoOfRows('Tickets_SQLServer');
FOR i=0 TO $(rows)-1
LET TicketNo = peek('Ticket_Num',$(i),'Tickets_SQLServer');
SQL SELECT * FROM TDW_base_views.Table WHERE TicketNbr = $(TicketNo);
you can't perform the where condition like that in qlikview..
Instead of that one you need to perform inner join between two tables like.
first load the Table from Sql server DB.
then load the table from TeraData DB.
perform the inner join between these two tables based on the Key Column.
establish the connectivity from sqlserver DB.
Load the first table from Sqlserver DB.
establsih the conncetivity from Teradata DB
load the second table from TeraData DB
thw above tables will join based on Id key.