Find a SQL query that returns false negative(s) over databases with null values. Then, propose a transformation that translates this query to a SQL query that does not return any false negative and retains all true positives delivered by the original query over databases with null values. You may also find a SQL query that returns false positives over databases with null values and transform it to a query that does not return any false positive and retains all true positives delivered by the original query over a database with null values.