this looks ok.  Maybe try 

zw myobj

before entering the loop, just to make sure that the file stream has linked up ok?

If you are on Windows, then you should have an .iris_history file on C:\Users\<yourusername>\.   Deleting this will clear your history

It's probably your date fields - typically SQL in code will run in Logical mode, not ODBC mode

Try explictly setting the SelectMode to ODBC and see if that helps?

https://docs.intersystems.com/irisforhealthlatest/csp/documatic/%25CSP.D...