奇奇怪怪的AUTO_INCREMENT
- 表格结构
- 先是这个亚子的
- 然后将另一个表，整个插入
- 删掉了第六行
- 结果再加入新的记录的时候
- 然后如果继续加入新的记录的话
- 如果把这些再删去并且再加入一条新记录，奇迹再现
- 但是的但，第一次删掉6，然后在9之后加入新记录直接为11到底咋回事。。。。。。。
-
表格结构
先是这个亚子的
然后将另一个表，整个插入
删掉了第六行
结果再加入新的记录的时候
然后如果继续加入新的记录的话
如果把这些再删去并且再加入一条新记录，奇迹再现
但是的但，第一次删掉6，然后在9之后加入新记录直接为11到底咋回事。。。。。。。
命令行执行的全过程如下
mysql> SHOW DATAbaseS;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test2_db |
| test_db |
+--------------------+
6 rows in set (0.00 sec)
mysql> use test2_db;
Database changed
mysql> show tables;
Empty set (0.00 sec)
mysql> CREATE TABLE t_class(classsno INT(11),cname VARCHAR(20),loc VARCHAR(40),advisor VARCHAR(20));
Query OK, 0 rows affected, 1 warning (0.07 sec)
mysql> DESC T_CLASS;
+----------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+-------+
| classsno | int | YES | | NULL | |
| cname | varchar(20) | YES | | NULL | |
| loc | varchar(40) | YES | | NULL | |
| advisor | varchar(20) | YES | | NULL | |
+----------+-------------+------+-----+---------+-------+
4 rows in set (0.01 sec)
mysql> INSERT INTO T_CLASS(classno,cname,loc,advisor)
-> VALUES(1,'高一（2）班','西教学楼三楼','张三');
ERROR 1054 (42S22): Unknown column 'classno' in 'field list'
mysql> ALTER TABLE T_CLASS CHANGE CLASSSNO classno;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
mysql> ALTER TABLE T_CLASS CHANGE CLASSSNO classno int;
Query OK, 0 rows affected (0.01 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> DESC T_CLASS;
+---------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| classno | int | YES | | NULL | |
| cname | varchar(20) | YES | | NULL | |
| loc | varchar(40) | YES | | NULL | |
| advisor | varchar(20) | YES | | NULL | |
+---------+-------------+------+-----+---------+-------+
4 rows in set (0.01 sec)
mysql> INSERT INTO T_CLASS(classno,cname,loc,advisor)
-> VALUES(1,'高一（2）班','西教学楼三楼','张三');
Query OK, 1 row affected (0.01 sec)
mysql> SELECt * FROM T_CLASS;
+---------+-------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+-------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
+---------+-------------+--------------+---------+
1 row in set (0.01 sec)
mysql> ALTER TABLE T_CLASS classno MODIFY classno INT(11) PRIMARY KEY AUTO_INCREMENT;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'classno MODIFY classno INT(11) PRIMARY KEY AUTO_INCREMENT' at line 1
mysql> ALTER TABLE T_CLASS classno INT(11) MODIFY classno INT(11) PRIMARY KEY AUTO_INCREMENT;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'classno INT(11) MODIFY classno INT(11) PRIMARY KEY AUTO_INCREMENT' at line 1
mysql> ALTER TABLE T_CLASS MODIFY classno INT(11) PRIMARY KEY AUTO_INCREMENT;
Query OK, 1 row affected, 1 warning (0.07 sec)
Records: 1 Duplicates: 0 Warnings: 1
mysql> ALTER TABLE T_CLASS MODIFY loc VARCHAR(40) DEFAULT '东教学楼2楼';
Query OK, 0 rows affected (0.04 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> SHOW COLUMNS FROM T_CLASS;
+---------+-------------+------+-----+-------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------+-------------+------+-----+-------------+----------------+
| classno | int | NO | PRI | NULL | auto_increment |
| cname | varchar(20) | YES | | NULL | |
| loc | varchar(40) | YES | | 东教学楼2楼 | |
| advisor | varchar(20) | YES | | NULL | |
+---------+-------------+------+-----+-------------+----------------+
4 rows in set (0.01 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES ('高一（8）班','西教学楼四楼');
Query OK, 1 row affected (0.01 sec)
mysql> SELECt * FROM T_CLASS;
+---------+-------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+-------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
| 2 | 高一（8）班 | 西教学楼四楼 | NULL |
+---------+-------------+--------------+---------+
2 rows in set (0.00 sec)
mysql> INSERT INTO T_CLASS VALUES(0,'高一（9）班','西教学楼五楼','高克谦'),(0,'高一（10）班','西教学楼六楼','张香桐'),(0,'高一（11）班','西教学楼 七楼','何基沣');
Query OK, 3 rows affected (0.01 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> SELECt * FROM T_CLASS;
+---------+--------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+--------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
| 2 | 高一（8）班 | 西教学楼四楼 | NULL |
| 3 | 高一（9）班 | 西教学楼五楼 | 高克谦 |
| 4 | 高一（10）班 | 西教学楼六楼 | 张香桐 |
| 5 | 高一（11）班 | 西教学楼七楼 | 何基沣 |
+---------+--------------+--------------+---------+
5 rows in set (0.00 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES ('高二某班','东教学楼某层'）,('高三某班','西教学楼某层');
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '）,('高三某班','西教学楼某层')' at line 1
mysql> SHOW ERRORS;
+-------+------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Level | Code | Message |
+-------+------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Error | 1064 | You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '）,('高三某班','西教学楼某层')' at line 1 |
+-------+------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> INSERT INTO T_CLASS (classno,cname,loc) VALUES (0,'高二某班','东教学楼某层'）,(0,'高三某班','西教学楼某层');
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '）,(0,'高三某班','西教学楼某层')' at line 1
mysql> INSERT INTO T_CLASS(cname,loc) VALUES('高二某班','东教学楼某层'）,('高三某班','西教学楼某层');
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '）,('高三某班','西教学楼某层')' at line 1
mysql> INSERT INTO T_CLASS(cname,loc) VALUES('高二某班','东教学楼某层'）,('高三某班','西教学楼某层');
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '）,('高三某班','西教学楼某层')' at line 1
mysql> INSERT INTO T_CLASS(cname,loc) VALUES('高二某班','东教学楼某层'）,('高三某班','西教学楼某层')
-> ;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '）,('高三某班','西教学楼某层')' at line 1
mysql> INSERT INTO T_CLASS(cname,loc)VALUES('高二某班','东教学楼某层'),('高三某班','西教学楼某层');
Query OK, 2 rows affected (0.01 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql> SELECt * FROM T_CLASS;
+---------+--------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+--------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
| 2 | 高一（8）班 | 西教学楼四楼 | NULL |
| 3 | 高一（9）班 | 西教学楼五楼 | 高克谦 |
| 4 | 高一（10）班 | 西教学楼六楼 | 张香桐 |
| 5 | 高一（11）班 | 西教学楼七楼 | 何基沣 |
| 6 | 高二某班 | 东教学楼某层 | NULL |
| 7 | 高三某班 | 西教学楼某层 | NULL |
+---------+--------------+--------------+---------+
7 rows in set (0.01 sec)
mysql> CREATE TABLE t_advisor(
-> id INT PRIMARY KEY,
-> aname VARCHAR(20),
-> loc VARCHAR(40),
-> advisor VARCHAR(20)
-> );
Query OK, 0 rows affected (0.08 sec)
mysql> ALTER TABLE T_ADVISOR MODIFY id VARCHAR(20),AUTO_INCREMENT;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
mysql> ALTER TABLE T_ADVISOR MODIFY id INT,AUTO_INCREMENT;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
mysql> ALTER TABLE T_ADVISOR MODIFY id INT AUTO_INCREMENT;
Query OK, 0 rows affected (0.07 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> DROp TABLE T_ADVISOR;
Query OK, 0 rows affected (0.02 sec)
mysql> SHOW TABLES;
+--------------------+
| Tables_in_test2_db |
+--------------------+
| t_class |
+--------------------+
1 row in set (0.01 sec)
mysql> CREATE TABLE t_advisor(
-> id INT PRIMARY KEY,
-> aname VARCHAR(20),
-> loc VARCHAR(40),
-> advisor VARCHAR(20)
-> );
Query OK, 0 rows affected (0.05 sec)
mysql> ALTER TABLE T_ADVISOR MODIFY ID INT AUTO_INCREMENT;
Query OK, 0 rows affected (0.11 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> DESCRIBE T_ADVISOR;
+---------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+----------------+
| ID | int | NO | PRI | NULL | auto_increment |
| aname | varchar(20) | YES | | NULL | |
| loc | varchar(40) | YES | | NULL | |
| advisor | varchar(20) | YES | | NULL | |
+---------+-------------+------+-----+---------+----------------+
4 rows in set (0.01 sec)
mysql> INSERT INTO T_ADVISOR VALUES(0,'C1','D1',X),(0,'C2','D2',Y);
ERROR 1054 (42S22): Unknown column 'X' in 'field list'
mysql> INSERT INTO T_ADVISOR VALUES(0,'C1','D1','X'),(0,'C2','D2','Y');
Query OK, 2 rows affected (0.01 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql> DESC T_ADVISOR;
+---------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+----------------+
| ID | int | NO | PRI | NULL | auto_increment |
| aname | varchar(20) | YES | | NULL | |
| loc | varchar(40) | YES | | NULL | |
| advisor | varchar(20) | YES | | NULL | |
+---------+-------------+------+-----+---------+----------------+
4 rows in set (0.01 sec)
mysql> SELECT * FROM T_ADVISOR;
+----+-------+------+---------+
| ID | aname | loc | advisor |
+----+-------+------+---------+
| 1 | C1 | D1 | X |
| 2 | C2 | D2 | Y |
+----+-------+------+---------+
2 rows in set (0.00 sec)
mysql> INSERT INTO T_CLASS (cname,loc) SELECt cname,loc FROM T_ADVISOR;
ERROR 1054 (42S22): Unknown column 'cname' in 'field list'
mysql> INSERT INTO T_CLASS (cname,loc) SELECt aname,loc FROM T_ADVISOR;
Query OK, 2 rows affected (0.01 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql> SELECt * FROM T_CLASS;
+---------+--------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+--------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
| 2 | 高一（8）班 | 西教学楼四楼 | NULL |
| 3 | 高一（9）班 | 西教学楼五楼 | 高克谦 |
| 4 | 高一（10）班 | 西教学楼六楼 | 张香桐 |
| 5 | 高一（11）班 | 西教学楼七楼 | 何基沣 |
| 6 | 高二某班 | 东教学楼某层 | NULL |
| 7 | 高三某班 | 西教学楼某层 | NULL |
| 8 | C1 | D1 | NULL |
| 9 | C2 | D2 | NULL |
+---------+--------------+--------------+---------+
9 rows in set (0.00 sec)
mysql> UPDATe T_CLASS SET loc='D3',advisor='E1' WHERe cname='C1';
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> SELECT * FROM T_CLASS;
+---------+--------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+--------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
| 2 | 高一（8）班 | 西教学楼四楼 | NULL |
| 3 | 高一（9）班 | 西教学楼五楼 | 高克谦 |
| 4 | 高一（10）班 | 西教学楼六楼 | 张香桐 |
| 5 | 高一（11）班 | 西教学楼七楼 | 何基沣 |
| 6 | 高二某班 | 东教学楼某层 | NULL |
| 7 | 高三某班 | 西教学楼某层 | NULL |
| 8 | C1 | D3 | E1 |
| 9 | C2 | D2 | NULL |
+---------+--------------+--------------+---------+
9 rows in set (0.01 sec)
mysql> UPDATe T_CLASS SET loc='loc_all',cname='cname_all' WHERe classno<=9&&classno>=8;
Query OK, 2 rows affected, 1 warning (0.01 sec)
Rows matched: 2 Changed: 2 Warnings: 1
mysql> SELECT * FROM T_CLASS;
+---------+--------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+--------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
| 2 | 高一（8）班 | 西教学楼四楼 | NULL |
| 3 | 高一（9）班 | 西教学楼五楼 | 高克谦 |
| 4 | 高一（10）班 | 西教学楼六楼 | 张香桐 |
| 5 | 高一（11）班 | 西教学楼七楼 | 何基沣 |
| 6 | 高二某班 | 东教学楼某层 | NULL |
| 7 | 高三某班 | 西教学楼某层 | NULL |
| 8 | cname_all | loc_all | E1 |
| 9 | cname_all | loc_all | NULL |
+---------+--------------+--------------+---------+
9 rows in set (0.01 sec)
mysql> DELETe T_CLASS WHERe cname='高二某班';
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERe cname='高二某班'' at line 1
mysql> DELETE FROM T_CLASS WHERe cname='高二某班';
Query OK, 1 row affected (0.01 sec)
mysql> SELECt * FROM T_CLASS;
+---------+--------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+--------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
| 2 | 高一（8）班 | 西教学楼四楼 | NULL |
| 3 | 高一（9）班 | 西教学楼五楼 | 高克谦 |
| 4 | 高一（10）班 | 西教学楼六楼 | 张香桐 |
| 5 | 高一（11）班 | 西教学楼七楼 | 何基沣 |
| 7 | 高三某班 | 西教学楼某层 | NULL |
| 8 | cname_all | loc_all | E1 |
| 9 | cname_all | loc_all | NULL |
+---------+--------------+--------------+---------+
8 rows in set (0.01 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES('cname_end','loc_end');
Query OK, 1 row affected (0.01 sec)
mysql> SELECt * FROM T_CLASS;
+---------+--------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+--------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
| 2 | 高一（8）班 | 西教学楼四楼 | NULL |
| 3 | 高一（9）班 | 西教学楼五楼 | 高克谦 |
| 4 | 高一（10）班 | 西教学楼六楼 | 张香桐 |
| 5 | 高一（11）班 | 西教学楼七楼 | 何基沣 |
| 7 | 高三某班 | 西教学楼某层 | NULL |
| 8 | cname_all | loc_all | E1 |
| 9 | cname_all | loc_all | NULL |
| 11 | cname_end | loc_end | NULL |
+---------+--------------+--------------+---------+
9 rows in set (0.01 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES('cname_end','loc_end');
Query OK, 1 row affected (0.01 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES('cname_end','loc_end');
Query OK, 1 row affected (0.01 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES('cname_end','loc_end');
Query OK, 1 row affected (0.01 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES('cname_end','loc_end');
Query OK, 1 row affected (0.00 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES('cname_end','loc_end');
Query OK, 1 row affected (0.01 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES('cname_end','loc_end');
Query OK, 1 row affected (0.01 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES('cname_end','loc_end');
Query OK, 1 row affected (0.00 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES('cname_end','loc_end');
Query OK, 1 row affected (0.00 sec)
mysql> select * from t_class;
+---------+--------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+--------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
| 2 | 高一（8）班 | 西教学楼四楼 | NULL |
| 3 | 高一（9）班 | 西教学楼五楼 | 高克谦 |
| 4 | 高一（10）班 | 西教学楼六楼 | 张香桐 |
| 5 | 高一（11）班 | 西教学楼七楼 | 何基沣 |
| 7 | 高三某班 | 西教学楼某层 | NULL |
| 8 | cname_all | loc_all | E1 |
| 9 | cname_all | loc_all | NULL |
| 11 | cname_end | loc_end | NULL |
| 12 | cname_end | loc_end | NULL |
| 13 | cname_end | loc_end | NULL |
| 14 | cname_end | loc_end | NULL |
| 15 | cname_end | loc_end | NULL |
| 16 | cname_end | loc_end | NULL |
| 17 | cname_end | loc_end | NULL |
| 18 | cname_end | loc_end | NULL |
| 19 | cname_end | loc_end | NULL |
+---------+--------------+--------------+---------+
17 rows in set (0.00 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES('cname_end','loc_end');
Query OK, 1 row affected (0.01 sec)
mysql> select * from t_class;
+---------+--------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+--------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
| 2 | 高一（8）班 | 西教学楼四楼 | NULL |
| 3 | 高一（9）班 | 西教学楼五楼 | 高克谦 |
| 4 | 高一（10）班 | 西教学楼六楼 | 张香桐 |
| 5 | 高一（11）班 | 西教学楼七楼 | 何基沣 |
| 7 | 高三某班 | 西教学楼某层 | NULL |
| 8 | cname_all | loc_all | E1 |
| 9 | cname_all | loc_all | NULL |
| 11 | cname_end | loc_end | NULL |
| 12 | cname_end | loc_end | NULL |
| 13 | cname_end | loc_end | NULL |
| 14 | cname_end | loc_end | NULL |
| 15 | cname_end | loc_end | NULL |
| 16 | cname_end | loc_end | NULL |
| 17 | cname_end | loc_end | NULL |
| 18 | cname_end | loc_end | NULL |
| 19 | cname_end | loc_end | NULL |
| 20 | cname_end | loc_end | NULL |
+---------+--------------+--------------+---------+
18 rows in set (0.00 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES('cname_end','loc_end');
Query OK, 1 row affected (0.01 sec)
mysql> select * from t_class;
+---------+--------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+--------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
| 2 | 高一（8）班 | 西教学楼四楼 | NULL |
| 3 | 高一（9）班 | 西教学楼五楼 | 高克谦 |
| 4 | 高一（10）班 | 西教学楼六楼 | 张香桐 |
| 5 | 高一（11）班 | 西教学楼七楼 | 何基沣 |
| 7 | 高三某班 | 西教学楼某层 | NULL |
| 8 | cname_all | loc_all | E1 |
| 9 | cname_all | loc_all | NULL |
| 11 | cname_end | loc_end | NULL |
| 12 | cname_end | loc_end | NULL |
| 13 | cname_end | loc_end | NULL |
| 14 | cname_end | loc_end | NULL |
| 15 | cname_end | loc_end | NULL |
| 16 | cname_end | loc_end | NULL |
| 17 | cname_end | loc_end | NULL |
| 18 | cname_end | loc_end | NULL |
| 19 | cname_end | loc_end | NULL |
| 20 | cname_end | loc_end | NULL |
| 21 | cname_end | loc_end | NULL |
+---------+--------------+--------------+---------+
19 rows in set (0.00 sec)
mysql> DELETe FROM T_CLASS WHERe classno<=21&&classno>=11;
Query OK, 11 rows affected, 1 warning (0.01 sec)
mysql> select * from t_class;
+---------+--------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+--------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
| 2 | 高一（8）班 | 西教学楼四楼 | NULL |
| 3 | 高一（9）班 | 西教学楼五楼 | 高克谦 |
| 4 | 高一（10）班 | 西教学楼六楼 | 张香桐 |
| 5 | 高一（11）班 | 西教学楼七楼 | 何基沣 |
| 7 | 高三某班 | 西教学楼某层 | NULL |
| 8 | cname_all | loc_all | E1 |
| 9 | cname_all | loc_all | NULL |
+---------+--------------+--------------+---------+
8 rows in set (0.00 sec)
mysql> INSERT INTO T_CLASS (cname,loc) VALUES('cname_end','loc_end');
Query OK, 1 row affected (0.01 sec)
mysql> select * from t_class;
+---------+--------------+--------------+---------+
| classno | cname | loc | advisor |
+---------+--------------+--------------+---------+
| 1 | 高一（2）班 | 西教学楼三楼 | 张三 |
| 2 | 高一（8）班 | 西教学楼四楼 | NULL |
| 3 | 高一（9）班 | 西教学楼五楼 | 高克谦 |
| 4 | 高一（10）班 | 西教学楼六楼 | 张香桐 |
| 5 | 高一（11）班 | 西教学楼七楼 | 何基沣 |
| 7 | 高三某班 | 西教学楼某层 | NULL |
| 8 | cname_all | loc_all | E1 |
| 9 | cname_all | loc_all | NULL |
| 22 | cname_end | loc_end | NULL |
+---------+--------------+--------------+---------+
9 rows in set (0.00 sec)
mysql>
