在Oracle中，可以使用以下方法來判斷null和空值：
SELECT * FROM table_name WHERE column_name IS NULL;
SELECT * FROM table_name WHERE column_name IS NOT NULL;
SELECT * FROM table_name WHERE NVL(column_name, 'default_value') = 'default_value';
SELECT * FROM table_name WHERE COALESCE(column1, column2, column3) IS NULL;
SELECT
CASE
WHEN column_name IS NULL THEN 'Null Value'
WHEN column_name = '' THEN 'Empty Value'
ELSE 'Not Null or Empty Value'
END AS value_type
FROM table_name;
