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- 兮珏 2021-06-10 10:09关注
-- 3~7题 -- ---------------------------- -- Table structure for grade -- ---------------------------- DROP TABLE IF EXISTS `grade`; CREATE TABLE `grade` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL, PRIMARY KEY (`id`) USING BTREE ) ENGINE = InnoDB AUTO_INCREMENT = 4 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic; -- 查看表结构 DESC student -- ---------------------------- -- Records of grade -- ---------------------------- INSERT INTO `grade` VALUES (1, '软件一班'); INSERT INTO `grade` VALUES (2, '软件二班'); INSERT INTO `grade` VALUES (3, '软件三班'); -- ---------------------------- -- Table structure for student -- ---------------------------- DROP TABLE IF EXISTS `student`; CREATE TABLE `student` ( `sid` int(11) NOT NULL AUTO_INCREMENT, `sname` varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL, `gid` int(11) NOT NULL, PRIMARY KEY (`sid`) USING BTREE ) ENGINE = InnoDB AUTO_INCREMENT = 7 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic; -- ---------------------------- -- Records of student -- ---------------------------- INSERT INTO `student` VALUES (1, '王红', 1); INSERT INTO `student` VALUES (2, '李强', 1); INSERT INTO `student` VALUES (3, '赵四', 2); INSERT INTO `student` VALUES (4, '郝娟', 2); INSERT INTO `student` VALUES (5, '段然', 3); INSERT INTO `student` VALUES (6, '李娟', 3); -- 8 SHOW TABLES -- 9 SELECT id FROM grade WHERE grade.name='软件一班' -- 10 SELECT * FROM student WHERE gid=1 -- 11 DELETE FROM student WHERE sname='王红' -- 12 UPDATE student SET gid=2 WHERE sname ='李强' -- 13 SELECT sid,sname FROM student WHERE gid=(SELECT id FROM grade WHERE grade.name='软件二班') -- 14 CREATE VIEW v_student as SELECT * FROM student
有偿就算了,多学点以后挣的钱都是自己的,这是最基础的知识了
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