It doesn't like the fact that you're trying to Create a view, while trying to read from it at the same time. Mine also returns
'CREATE VIEW' must be the first statement in a query batch
.
As digimanus suggests, first create the view, then try to query data from it.
string selectCommandTemperature = "SELECT TOP " + countTempe + " [T/°C] FROM (SELECT [T/°C] FROM Q3B
UNION
SELECT [T/°C] FROM Q3D) as t";