Mysql 修改別字段 change和modify的區別

表描述:

mysql> desc test;
+-------+----------+------+-----+---------+-------+
| Field | Type     | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+-------+
| id    | int(10) | YES | | NULL | | | name | char(10) | YES | | NULL | | +-------+----------+------+-----+---------+-------+ 2 rows in set (0.01 sec)

MySQL 中 change 和 modify 區別

• 更改列名 change: alter table 表名 change 舊列名 新列名 類型

mysql> alter table test change name name_1 int(10); Query OK, 0 rows affected (0.02 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> desc test; +----------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +----------+---------+------+-----+---------+-------+ | id | int(10) | YES | | NULL | | | name_1 | int(10) | YES | | NULL | | +----------+---------+------+-----+---------+-------+ 2 rows in set (0.00 sec)

只更改列屬性 change: alter table 表名 列名 列名 類型 相同的列名要寫兩次

mysql> alter table test change  name_1 name_1 char(32); Query OK, 0 rows affected (0.15 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> desc test; +----------+----------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +----------+----------+------+-----+---------+-------+ | id | int(10) | YES | | NULL | | | name_1 | char(32) | YES | | NULL | | +----------+----------+------+-----+---------+-------+ 2 rows in set (0.01 sec)

更改列屬性 modify: alter table 表名 列名 類型

mysql> desc test;
+----------+----------+------+-----+---------+-------+
| Field    | Type     | Null | Key | Default | Extra |
+----------+----------+------+-----+---------+-------+
| id       | int(10) | YES | | NULL | | | name_1 | char(32) | YES | | NULL | | +----------+----------+------+-----+---------+-------+ 2 rows in set (0.01 sec) mysql> alter table test modify name_1 int(10); Query OK, 0 rows affected (0.02 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> desc test; +----------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +----------+---------+------+-----+---------+-------+ | id | int(10) | YES | | NULL | | | name_1 | int(10) | YES | | NULL | | +----------+---------+------+-----+---------+-------+ 2 rows in set (0.00 sec)

change 可以更改列名 和 列類型 (每次都要把新列名和舊列名寫上, 即使兩個列名沒有更改,只是改了類型)
modify 只能更改列屬性 只需要寫一次列名, 比change 省事點