让我们了解 MySQL 客户端-服务器端帮助 -

mysql> help search_string

如果为上述“help”命令提供了参数，mysql将使用它作为搜索字符串来访问MySQL参考手册内容中的服务器端帮助。该命令的正确操作需要使用帮助主题信息初始化mysql数据库中的帮助表。

如果搜索字符串没有匹配，则搜索操作失败。让我们举个例子来理解这一点 -

mysql> help me

输出

Nothing found
Please try to run 'help contents' for a list of all accessible topics

我们可以使用帮助内容命令来查看帮助类别的列表。让我们举个例子来理解这一点 -

mysql> help contents

输出

You asked for help about help category: "Contents"
For more information, type 'help ', where  is one of the
following categories:
   Account Management
   Administration
   Data Definition
   Data Manipulation
   Data Types
   Functions
   Functions and Modifiers for Use with GROUP BY
   Geographic Features
   Language Structure
   Plugins
   Storage Engines
   Stored Routines
   Table Maintenance
   Transactions
   Triggers

如果搜索字符串匹配多个项目，那么 mysql 将显示匹配主题的列表。让我们举个例子来理解这一点 -

mysql > help logs

输出

Many help items for your request exist.
To make a more specific request, please type 'help ',
where  is one of the following topics:
   SHOW
   SHOW BINARY LOGS
   SHOW ENGINE
   SHOW LOGS