The method of adding fields to mysql

This article mainly introduces the method of adding fields to mysql, which has a certain reference value and can be used for reference by friends who need it. I hope you will learn a lot after reading this article. Next, let the editor take you to learn about it.

When writing sql statements in MySQL, it is very important to add fields, for example, when the created table is not enough to meet the requirements, you need to add fields, which has met the requirements.

First, take the table created below as an example:

CREATE TABLE IF NOT EXISTS `user` (`id` INT UNSIGNED AUTO_INCREMENT, `phone` CHAR (11) NOT NULL DEFAULT'', PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8

In the past, only the mobile phone number was saved, but now the information is more complete, and the name and creation time are required.

At this point, you need to use the method of adding fields.

ALTER TABLE `user`ADD `username` varchar (20) NULL DEFAULT''COMMENT' username 'AFTER `phone`, ADD `create_ at`username` creation time' AFTER `username`

AFTER means to add after a field. If not, add it to the end.

When creating tables and referring to other people's tables, it takes time to set up templates, such as using Navicat Premium tools to view other people's table information.

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