mysql alter table修改表命令整理_Mysql_脚本之家

1、向表employee中添加Account_Number字段并设置其字段类型为INT

ALTER [IGNORE] TABLE tbl_name alter_spec [, alter_spec ...] alter_specification: ADD [COLUMN] create_definition [FIRST | AFTER column_name ] or ADD INDEX [index_name]  or ADD PRIMARY KEY  or ADD UNIQUE [index_name]  or ALTER [COLUMN] col_name {SET DEFAULT literal | DROP DEFAULT} or CHANGE [COLUMN] old_col_name create_definition or MODIFY [COLUMN] create_definition or DROP [COLUMN] col_name or DROP PRIMARY KEY or DROP INDEX index_name or RENAME [AS] new_tbl_name or table_options 

ALTER TABLE employee DROP PRIMARY KEY

7、删除employee表中所有主键

11、多命令写在一起:

ALTER TABLE employee MODIFY First_Name varchar

5、将employee表中的id字段重命名为salary并设置其数据类型为int

10、将表employee重命名为Customer

MYSQL ALTER TABLE命令用于修改表结构,例如添加/修改/删除字段、索引、主键等等,本文章通过实例向大家介绍MYSQL ALTER TABLE语句的使用方法,

ALTER TABLE employee DROP INDEX Customer_ID

mysql> ALTER TABLE Books -> ADD PRIMARY KEY , -> ADD CONSTRAINT fk_1 FOREIGN KEY  REFERENCES Publishers , -> ADD COLUMN Format ENUM('paperback', 'hardcover') NOT NULL AFTER BookName;

8、删除employee表中字段Customer_ID的索引,只是将Customer_ID的索引取消,不会删除Customer_ID字段。

ALTER TABLE employee RENAME Customer

感谢阅读此文,希望能帮助到大家,谢谢大家对本站的支持!

ALTER TABLE employee CHANGE ID salary INT

ALTER TABLE employee DROP Customer_ID

ALTER TABLE employee ADD COLUMN Account_Number INT

6、删除employee表中的Customer_ID字段

ALTER TABLE employee ADD PRIMARY KEY

2、修改表employee中的ID字段为索引

ALTER TABLE employee ADD INDEX

ALTER TABLE employee ADD UNIQUE

3、修改表employee中的ID字段为主键PRIMARY KEY

9、修改employee表中First_Name的字段类型为varchar

MySQL ALTER语法如下:

4、修改表employee中的ID字段为唯一索引UNIQUE

本文由金沙官网线上发布于数据库,转载请注明出处:mysql alter table修改表命令整理_Mysql_脚本之家

您可能还会对下面的文章感兴趣: