在MySQL中帮助的使用主要有以下两个方面：

1 按层次查找帮助：?|help + 类别名称

mysql> ? contents;                #有哪些分类

You asked for help about help category: "Contents"

For more information, type ‘help <item>‘, where <item> is one of the following

categories:

   Account Management

   Administration

   Compound Statements

   Data Definition

   Data Manipulation

   Data Types

   Functions

   Functions and Modifiers for Use with GROUP BY

   Geographic Features

   Help Metadata

mysql> ? data types                #查看数据有哪些类型

You asked for help about help category: "Data Types"

For more information, type ‘help <item>‘, where <item> is one of the following

topics:

   AUTO_INCREMENT

   BIGINT

   BINARY

   BIT

   BLOB

   BLOB DATA TYPE

   BOOLEAN

   CHAR

   CHAR BYTE

   DATE

   DATETIME

   DEC

   DECIMAL

mysql> help int;                    #关于数据类型的说明

Name: ‘INT‘

Description:

INT[(M)] [UNSIGNED] [ZEROFILL]

A normal-size integer. The signed range is -2147483648 to 2147483647.

The unsigned range is 0 to 4294967295.

2 快速查阅帮助

mysql> ? create database;

Name: ‘CREATE DATABASE‘

Description:

Syntax:

CREATE {DATABASE | SCHEMA} [IF NOT EXISTS] db_name

    [create_specification] ...

create_specification:

    [DEFAULT] CHARACTER SET [=] charset_name

  | [DEFAULT] COLLATE [=] collation_name

CREATE DATABASE creates a database with the given name. To use this

statement, you need the CREATE privilege for the database. CREATE

SCHEMA is a synonym for CREATE DATABASE.

......

mysql> help create table;

Name: ‘CREATE TABLE‘

Description:

Syntax:

CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name

    (create_definition,...)

    [table_options]

    [partition_options]

CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name

    [(create_definition,...)]

    [table_options]

    [partition_options]

    select_statement

CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name

    { LIKE old_tbl_name | (LIKE old_tbl_name) }

......

本文出自 “一万年太久，只争朝夕” 博客，请务必保留此出处http://zengwj1949.blog.51cto.com/10747365/1920336

MySQL之帮助的使用