MySQL資料庫在指定位置增加欄位
阿新 • • 發佈:2018-12-19
這個本身屬於MySQL的基本語法,我這裡給出一個例子而已。
[java] view plain copy print?- mysql> -- 測試資料庫在指定位置增加欄位
- mysql> drop table if exists t;
- Query OK, 0 rows affected (0.06 sec)
- mysql> create table t(age int,address varchar(50));
- Query OK, 0 rows affected (0.06 sec)
- mysql> desc t;
- +---------+-------------+------+-----+---------+-------+
- | Field | Type | Null | Key | Default | Extra |
- +---------+-------------+------+-----+---------+-------+
- | age | int(11) | YES | | NULL | |
- | address | varchar(50) | YES | | NULL | |
- +---------+-------------+------+-----+---------+-------+
- 2 rows in set (
- mysql> alter table t add column name varchar(20) after age;
- Query OK, 0 rows affected (0.16 sec)
- Records: 0 Duplicates: 0 Warnings: 0
- mysql> desc t;
- +---------+-------------+------+-----+---------+-------+
- | Field | Type | Null | Key | Default | Extra |
- +---------+-------------+------+-----+---------+-------+
- | age | int(11) | YES | | NULL | |
- | name | varchar(20) | YES | | NULL | |
- | address | varchar(50) | YES | | NULL | |
- +---------+-------------+------+-----+---------+-------+
- 3 rows in set (0.00 sec)
- mysql> alter table t add column id int FIRST;
- Query OK, 0 rows affected (0.13 sec)
- Records: 0 Duplicates: 0 Warnings: 0
- mysql> desc t;
- +---------+-------------+------+-----+---------+-------+
- | Field | Type | Null | Key | Default | Extra |
- +---------+-------------+------+-----+---------+-------+
- | id | int(11) | YES | | NULL | |
- | age | int(11) | YES | | NULL | |
- | name | varchar(20) | YES | | NULL | |
- | address | varchar(50) | YES | | NULL | |
- +---------+-------------+------+-----+---------+-------+
- 4 rows in set (0.00 sec)
- mysql>
相關的語法描述為
ALTER [ONLINE | OFFLINE] [IGNORE] TABLE tbl_name alter_specification [, alter_specification] ...alter_specification: table_option ... | ADD [COLUMN] col_name column_definition [FIRST | AFTER col_name ]