SET CONNECTION — select a database connection
SET CONNECTION [ TO | = ] connection_name
     SET CONNECTION sets the “current”
     database connection, which is the one that all commands use
     unless overridden.
    
connection_name
        A database connection name established by
        the CONNECT command.
       
DEFAULTSet the connection to the default connection.
EXEC SQL SET CONNECTION TO con2; EXEC SQL SET CONNECTION = con1;
     SET CONNECTION is specified in the SQL standard.