Just as the error says, the CREATE VIEW statement needs to be the only statement in the query batch.

You have two option in this scenario, depending on the functionality you want to achieve:

1. Place the CREATE VIEW query at the beginning

   CREATE VIEW showing
   as
   select tradename, unitprice, GenericFlag
   from Medicine;
   
   with ExpAndCheapMedicine(MostMoney, MinMoney) as
   (
       select max(unitprice), min(unitprice)
       from Medicine
   )
   ,
   findmostexpensive(nameOfExpensive) as
   (
       select tradename
       from Medicine, ExpAndCheapMedicine
       where UnitPrice = MostMoney
   )
   ,
   findCheapest(nameOfCheapest) as
   (
       select tradename
       from Medicine, ExpAndCheapMedicine
           where UnitPrice = MinMoney
       )
   

2. Use GO after the CTE and before the CREATE VIEW query

   — Option #2

   with ExpAndCheapMedicine(MostMoney, MinMoney) as
   (
       select max(unitprice), min(unitprice)
       from Medicine
   )
   ,
   findmostexpensive(nameOfExpensive) as
   (
       select tradename
       from Medicine, ExpAndCheapMedicine
       where UnitPrice = MostMoney
   )
   ,
   findCheapest(nameOfCheapest) as
   (
       select tradename
       from Medicine, ExpAndCheapMedicine
       where UnitPrice = MinMoney
   )
   
   GO    
   
   CREATE VIEW showing
   as
   select tradename, unitprice, GenericFlag
   from Medicine;

Create View needs to add Go up and down, if there are other SQL up and down