MySQL数据库在指定位置增加字段

这个本身属于MySQL的基本语法，我这里给出一个例子而已。

view plaincopy to clipboardprint?mysql> -- 测试数据库在指定位置增加字段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 (0.02 sec)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>mysql> -- 测试数据库在指定位置增加字段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 (0.02 sec)mysql> alter table t add column name varchar(20) after age;Query OK, 0 rows affected (0.16 sec)Records: 0; Duplicates: 0; Warnings: 0mysql> 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: 0mysql> 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>

相关的语法描述为

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 ]