高效查看MySQL帮助文档的方法（转）

2023-08-02 20:36:40

在mysql的使用过程中, 可能经常会遇到以下问题:

某个操作语法忘记了, 如何快速查找?
如何快速知道当前版本上某个字段类型的取值范围?
当前版本都支持哪些函数?希望有例子说明..
当前版本是否支持某个功能?

对于上面列出的问题, 我们可能想到的方法是查找MySQL的文档, 这些问题在官方文档都可以很清楚地查到, 但是却要耗费大量的时间和精力.

所以对于以上问题, 最好的解决办法就是使用MySQL安装后自带的帮助文档, 这样在遇到问题时就可以方便快捷地进行查询.

按层次查看帮助

查看目录

如果不知道帮助能够提供些什么, 可以用"? contents"命令来显示所有可供查询的分类, 如下例所示:

mysql> ? contents
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
Language Structure
Plugins
Procedures
Storage Engines
Table Maintenance
Transactions
User-Defined Functions
Utility

mysql> ? contents

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

   Language Structure

   Plugins

   Procedures

   Storage Engines

   Table Maintenance

   Transactions

   User-Defined Functions

   Utility

查看数据类型

对于列出的分类, 可以使用"? 类别名称"的方式针对用户感兴趣的内容做进一步的查看, 例如, 想看看MySQL都支持哪些数据类型, 可以执行"? data tyeps"命令:

mysql> ? data types
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
DOUBLE
DOUBLE PRECISION
ENUM
FLOAT
INT
INTEGER
LONGBLOB
LONGTEXT
MEDIUMBLOB
MEDIUMINT
MEDIUMTEXT
SET DATA TYPE
SMALLINT
TEXT
TIME
TIMESTAMP
TINYBLOB
TINYINT
TINYTEXT
VARBINARY
VARCHAR
YEAR DATA TYPE

mysql> ? data types

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

   DOUBLE

   DOUBLE PRECISION

   ENUM

   FLOAT

   INT

   INTEGER

   LONGBLOB

   LONGTEXT

   MEDIUMBLOB

   MEDIUMINT

   MEDIUMTEXT

   SET DATA TYPE

   SMALLINT

   TEXT

   TIME

   TIMESTAMP

   TINYBLOB

   TINYINT

   TINYTEXT

   VARBINARY

   VARCHAR

   YEAR DATA TYPE

上面列出了此版本支持的所有数据类型, 如果想知道int类型的具体介绍, 也可以利用上面的方法, 做进一步的查看:

mysql> ? int
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.
URL: http://dev.mysql.com/doc/refman/5.5/en/numeric-type-overview.html

mysql> ? int

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.

URL: http://dev.mysql.com/doc/refman/5.5/en/numeric-type-overview.html

查看函数

mysql> ? functions
You asked for help about help category: "Functions"
For more information, type 'help <item>', where <item> is one of the following
categories:
Bit Functions
Comparison operators
Control flow functions
Date and Time Functions
Encryption Functions
Information Functions
Logical operators
Miscellaneous Functions
Numeric Functions
String Functions

mysql> ? functions

You asked for help about help category: "Functions"

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

categories:

   Bit Functions

   Comparison operators

   Control flow functions

   Date and Time Functions

   Encryption Functions

   Information Functions

   Logical operators

   Miscellaneous Functions

   Numeric Functions

   String Functions

再根据列出的目录查看相应函数,比如查看都有什么日期函数

mysql> ? Date and Time Functions
You asked for help about help category: "Date and Time Functions"
For more information, type 'help <item>', where <item> is one of the following
topics:
ADDDATE
ADDTIME
CONVERT_TZ
CURDATE
CURRENT_DATE
CURRENT_TIME
CURRENT_TIMESTAMP
CURTIME
DATE FUNCTION
DATEDIFF
DATE_ADD
DATE_FORMAT
DATE_SUB
DAY
DAYNAME
DAYOFMONTH
DAYOFWEEK
DAYOFYEAR
EXTRACT
FROM_DAYS
FROM_UNIXTIME
GET_FORMAT
HOUR
LAST_DAY
LOCALTIME
LOCALTIMESTAMP
MAKEDATE
MAKETIME
MICROSECOND
MINUTE
MONTH
MONTHNAME
NOW
PERIOD_ADD
PERIOD_DIFF
QUARTER
SECOND
SEC_TO_TIME
STR_TO_DATE
SUBDATE
SUBTIME
SYSDATE
TIME FUNCTION
TIMEDIFF
TIMESTAMP FUNCTION
TIMESTAMPADD
TIMESTAMPDIFF
TIME_FORMAT
TIME_TO_SEC
TO_DAYS
TO_SECONDS
UNIX_TIMESTAMP
UTC_DATE
UTC_TIME
UTC_TIMESTAMP
WEEK
WEEKDAY
WEEKOFYEAR
YEAR
YEARWEEK

mysql> ? Date and Time Functions

You asked for help about help category: "Date and Time Functions"

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

topics:

   ADDDATE

   ADDTIME

   CONVERT_TZ

   CURDATE

   CURRENT_DATE

   CURRENT_TIME

   CURRENT_TIMESTAMP

   CURTIME

   DATE FUNCTION

   DATEDIFF

   DATE_ADD

   DATE_FORMAT

   DATE_SUB

   DAY

   DAYNAME

   DAYOFMONTH

   DAYOFWEEK

   DAYOFYEAR

   EXTRACT

   FROM_DAYS

   FROM_UNIXTIME

   GET_FORMAT

   HOUR

   LAST_DAY

   LOCALTIME

   LOCALTIMESTAMP

   MAKEDATE

   MAKETIME

   MICROSECOND

   MINUTE

   MONTH

   MONTHNAME

   NOW

   PERIOD_ADD

   PERIOD_DIFF

   QUARTER

   SECOND

   SEC_TO_TIME

   STR_TO_DATE

   SUBDATE

   SUBTIME

   SYSDATE

   TIME FUNCTION

   TIMEDIFF

   TIMESTAMP FUNCTION

   TIMESTAMPADD

   TIMESTAMPDIFF

   TIME_FORMAT

   TIME_TO_SEC

   TO_DAYS

   TO_SECONDS

   UNIX_TIMESTAMP

   UTC_DATE

   UTC_TIME

   UTC_TIMESTAMP

   WEEK

   WEEKDAY

   WEEKOFYEAR

   YEAR

   YEARWEEK

快速查阅帮助

在实际应用当中, 如果需要快速查阅某项语法时, 可以使用关键字进行快速查询. 例如, 想知道show命令都能看到什么东西, 可以用如下命令:

mysql> ? show
Name: 'SHOW'
Description:
SHOW has many forms that provide information about databases, tables,
columns, or status information about the server. This section describes
those following:
SHOW AUTHORS
SHOW {BINARY | MASTER} LOGS
SHOW BINLOG EVENTS [IN 'log_name'] [FROM pos] [LIMIT [offset,] row_count]
SHOW CHARACTER SET [like_or_where]
SHOW COLLATION [like_or_where]
SHOW [FULL] COLUMNS FROM tbl_name [FROM db_name] [like_or_where]
SHOW CONTRIBUTORS
SHOW CREATE DATABASE db_name
SHOW CREATE EVENT event_name
SHOW CREATE FUNCTION func_name
SHOW CREATE PROCEDURE proc_name
SHOW CREATE TABLE tbl_name
SHOW CREATE TRIGGER trigger_name
SHOW CREATE VIEW view_name
SHOW DATABASES [like_or_where]
SHOW ENGINE engine_name {STATUS | MUTEX}
SHOW [STORAGE] ENGINES
SHOW ERRORS [LIMIT [offset,] row_count]
SHOW EVENTS
SHOW FUNCTION CODE func_name
SHOW FUNCTION STATUS [like_or_where]
SHOW GRANTS FOR user
SHOW INDEX FROM tbl_name [FROM db_name]
SHOW MASTER STATUS
SHOW OPEN TABLES [FROM db_name] [like_or_where]
SHOW PLUGINS
SHOW PROCEDURE CODE proc_name
SHOW PROCEDURE STATUS [like_or_where]
SHOW PRIVILEGES
SHOW [FULL] PROCESSLIST
SHOW PROFILE [types] [FOR QUERY n] [OFFSET n] [LIMIT n]
SHOW PROFILES
SHOW SLAVE HOSTS
SHOW SLAVE STATUS
SHOW [GLOBAL | SESSION] STATUS [like_or_where]
SHOW TABLE STATUS [FROM db_name] [like_or_where]
SHOW [FULL] TABLES [FROM db_name] [like_or_where]
SHOW TRIGGERS [FROM db_name] [like_or_where]
SHOW [GLOBAL | SESSION] VARIABLES [like_or_where]
SHOW WARNINGS [LIMIT [offset,] row_count]
like_or_where:
LIKE 'pattern'
| WHERE expr
If the syntax for a given SHOW statement includes a LIKE 'pattern'
part, 'pattern' is a string that can contain the SQL "%" and "_"
wildcard characters. The pattern is useful for restricting statement
output to matching values.
Several SHOW statements also accept a WHERE clause that provides more
flexibility in specifying which rows to display. See
http://dev.mysql.com/doc/refman/5.5/en/extended-show.html.
URL: http://dev.mysql.com/doc/refman/5.5/en/show.html

mysql> ? show

Name: 'SHOW'

Description:

SHOW has many forms that provide information about databases, tables,

columns, or status information about the server. This section describes

those following:

SHOW AUTHORS

SHOW {BINARY | MASTER} LOGS

SHOW BINLOG EVENTS [IN 'log_name'] [FROM pos] [LIMIT [offset,] row_count]

SHOW CHARACTER SET [like_or_where]

SHOW COLLATION [like_or_where]

SHOW [FULL] COLUMNS FROM tbl_name [FROM db_name] [like_or_where]

SHOW CONTRIBUTORS

SHOW CREATE DATABASE db_name

SHOW CREATE EVENT event_name

SHOW CREATE FUNCTION func_name

SHOW CREATE PROCEDURE proc_name

SHOW CREATE TABLE tbl_name

SHOW CREATE TRIGGER trigger_name

SHOW CREATE VIEW view_name

SHOW DATABASES [like_or_where]

SHOW ENGINE engine_name {STATUS | MUTEX}

SHOW [STORAGE] ENGINES

SHOW ERRORS [LIMIT [offset,] row_count]

SHOW EVENTS

SHOW FUNCTION CODE func_name

SHOW FUNCTION STATUS [like_or_where]

SHOW GRANTS FOR user

SHOW INDEX FROM tbl_name [FROM db_name]

SHOW MASTER STATUS

SHOW OPEN TABLES [FROM db_name] [like_or_where]

SHOW PLUGINS

SHOW PROCEDURE CODE proc_name

SHOW PROCEDURE STATUS [like_or_where]

SHOW PRIVILEGES

SHOW [FULL] PROCESSLIST

SHOW PROFILE [types] [FOR QUERY n] [OFFSET n] [LIMIT n]

SHOW PROFILES

SHOW SLAVE HOSTS

SHOW SLAVE STATUS

SHOW [GLOBAL | SESSION] STATUS [like_or_where]

SHOW TABLE STATUS [FROM db_name] [like_or_where]

SHOW [FULL] TABLES [FROM db_name] [like_or_where]

SHOW TRIGGERS [FROM db_name] [like_or_where]

SHOW [GLOBAL | SESSION] VARIABLES [like_or_where]

SHOW WARNINGS [LIMIT [offset,] row_count]

like_or_where:

    LIKE 'pattern'

  | WHERE expr

If the syntax for a given SHOW statement includes a LIKE 'pattern'

part, 'pattern' is a string that can contain the SQL "%" and "_"

wildcard characters. The pattern is useful for restricting statement

output to matching values.

Several SHOW statements also accept a WHERE clause that provides more

flexibility in specifying which rows to display. See

http://dev.mysql.com/doc/refman/5.5/en/extended-show.html.

URL: http://dev.mysql.com/doc/refman/5.5/en/show.html

例如, 想查看某个函数CONCAT的使用

mysql> ? concat
Name: 'CONCAT'
Description:
Syntax:
CONCAT(str1,str2,...)
Returns the string that results from concatenating the arguments. May
have one or more arguments. If all arguments are nonbinary strings, the
result is a nonbinary string. If the arguments include any binary
strings, the result is a binary string. A numeric argument is converted
to its equivalent string form. This is a nonbinary string as of MySQL
5.5.3. Before 5.5.3, it is a binary string; to to avoid that and
produce a nonbinary string, you can use an explicit type cast, as in
this example:
SELECT CONCAT(CAST(int_col AS CHAR), char_col);
CONCAT() returns NULL if any argument is NULL.
URL: http://dev.mysql.com/doc/refman/5.5/en/string-functions.html
Examples:
mysql> SELECT CONCAT('My', 'S', 'QL');
-> 'MySQL'
mysql> SELECT CONCAT('My', NULL, 'QL');
-> NULL
mysql> SELECT CONCAT(14.3);
-> '14.3'

mysql> ? concat

Name: 'CONCAT'

Description:

Syntax:

CONCAT(str1,str2,...)

Returns the string that results from concatenating the arguments. May

have one or more arguments. If all arguments are nonbinary strings, the

result is a nonbinary string. If the arguments include any binary

strings, the result is a binary string. A numeric argument is converted

to its equivalent string form. This is a nonbinary string as of MySQL

5.5.3. Before 5.5.3, it is a binary string; to to avoid that and

produce a nonbinary string, you can use an explicit type cast, as in

this example:

SELECT CONCAT(CAST(int_col AS CHAR), char_col);

CONCAT() returns NULL if any argument is NULL.

URL: http://dev.mysql.com/doc/refman/5.5/en/string-functions.html

Examples:

mysql> SELECT CONCAT('My', 'S', 'QL');

        -> 'MySQL'

mysql> SELECT CONCAT('My', NULL, 'QL');

        -> NULL

mysql> SELECT CONCAT(14.3);

        -> '14.3'

又例如, 如果想查看create table的语法, 可以使用以下命令:

mysql> ? create table
Name: 'CREATE TABLE'
Description:
Syntax:
CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
(create_definition,...)
[table_options]
[partition_options]
Or:
CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
[(create_definition,...)]
[table_options]
[partition_options]
select_statement
Or:
CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
{ LIKE old_tbl_name | (LIKE old_tbl_name) }
......

mysql> ? create table

Name: 'CREATE TABLE'

Description:

Syntax:

CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name

    (create_definition,...)

    [table_options]

    [partition_options]

Or:

CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name

    [(create_definition,...)]

    [table_options]

    [partition_options]

    select_statement

Or:

CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name

    { LIKE old_tbl_name | (LIKE old_tbl_name) }

    ......

再举一个例子吧, 比如想查看创建用户GRANT语法怎么写

mysql> ? grant
Name: 'GRANT'
Description:
Syntax:
GRANT
priv_type [(column_list)]
[, priv_type [(column_list)]] ...
ON [object_type] priv_level
TO user_specification [, user_specification] ...
[REQUIRE {NONE | ssl_option [[AND] ssl_option] ...}]
[WITH with_option ...]
GRANT PROXY ON user_specification
TO user_specification [, user_specification] ...
[WITH GRANT OPTION]
object_type:
TABLE
| FUNCTION
| PROCEDURE
......

mysql> ? grant

Name: 'GRANT'

Description:

Syntax:

GRANT

    priv_type [(column_list)]

      [, priv_type [(column_list)]] ...

    ON [object_type] priv_level

    TO user_specification [, user_specification] ...

    [REQUIRE {NONE | ssl_option [[AND] ssl_option] ...}]

    [WITH with_option ...]

GRANT PROXY ON user_specification

    TO user_specification [, user_specification] ...

    [WITH GRANT OPTION]

object_type:

    TABLE

  | FUNCTION

  | PROCEDURE

      ......

下面把查看手册和官方资料的地址献上, 就把衣钵都传给你们了, 别忘了给个赞哦~

常用的网络资源

http://dev.mysql.com/downloads/是MySQL的官方网站,
可以下载到各个版本的MySQL以及相关客户端开发工具等.

http://dev.mysql.com/doc/提供了目前最权威的MySQL数据库及工具的在线手册

http://bugs.mysql.com/ 这里可以查看到MySQL已经发布的bug列表,
或者向MySQL提交bug报告

http://www.mysql.com/news-and-events/newsletter/通常会发布各种关于MySQL的最新消息.

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