I"m trying to write a query in Oracle SQL to return rows if the value in field 1 does not equal the value in field 2 (where field2 includes some null values)

If the table looks like this

Field1    Field2
1         1
2         3
4         

If I use this query:

select * from table where field1 != field2

I only get back row 2, but not row 3. Is there a single query I can use to get both rows 2,3 retreived?