SELECT * FROM courses WHERE LOWER(education_delivery_method) = 'classroom';
SELECT UPPER(SUBSTR(lastname,1,1)) || LOWER(SUBSTR(lastname,2,29))
FROM students WHERE rownum < 11;
UPDATE students SET lastname = UPPER(lastname) WHERE lastname = 'Jones';
COMMIT;
SELECT UPPER(firstname) AS "FIRSTNAME", lastname
FROM students WHERE rownum < 11;
核心：LOWER/UPPER 配合 SUBSTR 實現靈活大小寫轉換，查詢與更新同理。
