如何在MySQL中从表中删除列 [英] How to delete a column from a table in MySQL

问题描述

给出使用以下命令创建的表:

Given the table created using:

CREATE TABLE tbl_Country
(
  CountryId INT NOT NULL AUTO_INCREMENT,
  IsDeleted bit,
  PRIMARY KEY (CountryId) 
)

如何删除列IsDeleted?

推荐答案

ALTER TABLE tbl_Country DROP COLUMN IsDeleted;

这是一个有效的示例.

请注意，COLUMN关键字是可选的，因为MySQL仅接受DROP IsDeleted.另外，要删除多列，您必须用逗号将它们分开，并为每列添加DROP.

Note that the COLUMN keyword is optional, as MySQL will accept just DROP IsDeleted. Also, to drop multiple columns, you have to separate them by commas and include the DROP for each one.

ALTER TABLE tbl_Country
  DROP COLUMN IsDeleted,
  DROP COLUMN CountryName;

这允许您在一个语句中的同一表上的DROP，ADD和ALTER多列.从 MySQL参考手册:

This allows you to DROP, ADD and ALTER multiple columns on the same table in the one statement. From the MySQL reference manual:

您可以在单个ALTER TABLE语句中以逗号分隔多个ADD，ALTER，DROP和CHANGE子句.这是对标准SQL的MySQL扩展，每个ALTER TABLE语句仅允许每个子句之一.

You can issue multiple ADD, ALTER, DROP, and CHANGE clauses in a single ALTER TABLE statement, separated by commas. This is a MySQL extension to standard SQL, which permits only one of each clause per ALTER TABLE statement.

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