小小的修改列的注释信息也能引发一些思考。

正确的修改方式要带上原来列的定义，如：

 ALTER TABLE `user` CHANGE `id` `id` INT( 11 ) COMMENT 'id of user';

高票答案的几个回复：

Note that altering a comment will cause a full resconstruction of the table. So you may choose to live without it on very big table.

修改列注释会重构表 （对于大表慎用）

That is not (or no longer) true, as long as the column definition matches the existing definition exactly. Comments can be added without causing table reconstruction.

如果和之前的列定义一致，修改列注释不会重构表

Alter MySQL table to add comments on columns