/*查詢表數據*/select * from STU

/*取出前3行數據*/select * from stu where ROWNUM<=3 

/*模糊查詢*/select * from stu where stu_id like 'stu001%'

/*別名*/select STU_ID as 學號 from stu

/*普通聯合查詢*/SELECT STU.STU_NAME, STU.STU_AGE, KC.KC_NAME FROM STU, KC WHERE STU.KC_NO = KC.KC_NO

/*聯合查詢*/SELECT STU.STU_NAME, STU.STU_AGE, KC.KC_NAME FROM STU INNER JOIN KC ON STU.KC_NO = KC.KC_NO ORDER BY STU.STU_ID 

/*左連接*/SELECT STU.STU_NAME, STU.STU_AGE, KC.KC_NAME FROM STU LEFT JOIN KC ON STU.KC_NO = KC.KC_NO ORDER BY STU.STU_ID 

/*右連接*/SELECT STU.STU_NAME, STU.STU_AGE, KC.KC_NAME FROM STU RIGHT JOIN KC ON STU.KC_NO = KC.KC_NO ORDER BY STU.STU_ID 

/*全連接*/SELECT STU.STU_NAME, STU.STU_AGE, KC.KC_NAME FROM STU FULL JOIN KC ON STU.KC_NO = KC.KC_NO ORDER BY STU.STU_ID 

/*UNION關鍵字，聯合兩個表某些字段*/SELECT STU_NAME FROM STU UNION SELECT KC_NAME FROM KC