Hi Nadya,

If i understood correctly, you want to change null values by empty values, isn' it? If so, You can use NVL funtion. This funtion returns a non-null value, between 2 variables.
Example:

a = .null.
b = "my value"
WAIT WINDOW NVL(a,b)

This will return "MY VALUE", because A was a null value, and B wans't.
You can include NVL at your SELECT statement.

Hope it helps. Nice to hear from you.

Ricardo