關(guān)于修測驗UTO_INCREMENT列的默認(rèn)值的測試

2024-09-07 22:12:41

字體：大中小

供稿：網(wǎng)友

其實是個很簡單的操作，但是忽然有人問我就是想不起來，暫且做個筆記在這里。

mysql> create table test2(id int(2) AUTO_INCREMENT,name varchar(10),primary key(id));
Query OK, 0 rows affected (0.03 sec)

mysql> insert into test2 values(null,'a'),(null,'b'),(null,'c');
Query OK, 3 rows affected (0.00 sec)
Records: 3 Duplicates: 0 Warnings: 0

mysql> select * from test2;
+----+------+
| id | name |
+----+------+
| 1 | a |
| 2 | b |
| 3 | c |
+----+------+
3 rows in set (0.00 sec)

mysql> delete from test2 where id in (2,3);
Query OK, 2 rows affected (0.00 sec)

mysql> select * from test2;
+----+------+
| id | name |
+----+------+
| 1 | a |
+----+------+
1 row in set (0.00 sec)

mysql> insert into test2 values(null,'d');
Query OK, 1 row affected (0.00 sec)

mysql> select * from test2;
+----+------+
| id | name |
+----+------+
| 1 | a |
| 4 | d |
+----+------+
2 rows in set (0.00 sec)

mysql> delete from test2 where id = 4;
Query OK, 1 row affected (0.00 sec)

mysql> alter table test2 AUTO_INCREMENT=2;
Query OK, 1 row affected (0.02 sec)
Records: 1 Duplicates: 0 Warnings: 0

mysql> insert into test2 values(null,'f');
Query OK, 1 row affected (0.00 sec)

mysql> select * from test2;
+----+------+
| id | name |
+----+------+
| 1 | a |
| 2 | f |
+----+------+
2 rows in set (0.00 sec)

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（編輯：武林網(wǎng)）

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