Mysql self-increasing column
1. Mysql creates a table with self-increasing columns
Create table inc (id int (10) not null auto_increment,name varchar (20), primary key (id))
Note:
Auto-increment column must be key
There are no quotation marks in the front id, and there can be no quotation marks when the back is set to key
2. Use self-incrementing column
Mysql > insert into inc values (id,'leo')
Query OK, 1 row affected (0.00 sec)
Mysql > select * from inc
+-+ +
| | id | name |
+-+ +
| | 1 | leo |
+-+ +
1 row in set (0.00 sec)
Mysql > insert into inc values (id,'dem')
Query OK, 1 row affected (0.00 sec)
Mysql > select * from inc
+-+ +
| | id | name |
+-+ +
| | 1 | leo |
| | 2 | dem |
+-+ +
2 rows in set (0.00 sec)
You can see that the self-increment column starts from 1 by default.
3. Set self-increment column
If you do not want the increment column to start at 1, you can use the following statement to modify the starting value of the increment
Alter table inc auto_increment=100
Mysql > insert into inc values (id,'jack')
Query OK, 1 row affected (0.01sec)
Mysql > select * from inc
+-+ +
| | id | name |
+-+ +
| | 1 | leo |
| | 2 | dem |
| | 100 | jack |
+-+ +
3 rows in set (0.00 sec)
