ORACLE学习笔记-查询篇

/*查询表数据*/select * from STU

/*取出前3行数据*/select * from stu where ROWNUM<=3 

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

/*别名*/select STU_ID as 学号 from stu

/*普通联合查询*/SELECT STU.STU_NAME, STU.STU_AGE, KC.KC_NAME FROM STU, KC WHERE STU.KC_NO = KC.KC_NO

/*联合查询*/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 

/*左连接*/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 

/*右连接*/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 

/*全连接*/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关键字，联合两个表某些字段*/SELECT STU_NAME FROM STU UNION SELECT KC_NAME FROM KC