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 askedforhelp about help category: "Contents"For more information, type 'help ', where is one ofthe following

categories:

Account Management

Administration

Compound Statements

Data Definition

Data Manipulation

Data Types

Functions

Functionsand Modifiers for Use with GROUP BYGeographic Features

Help Metadata

Language Structure

Plugins

Procedures

Storage EnginesTableMaintenance

TransactionsUser-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 askedforhelp about help category: "Data Types"For more information, type 'help ', where is one ofthe following

topics:

AUTO_INCREMENTBIGINT

BINARY

BITBLOB

BLOB DATA TYPE

BOOLEANCHAR

CHARBYTE

DATEDATETIME

DEC

DECIMAL

DOUBLE

DOUBLE PRECISIONENUMFLOAT

INT

INTEGERLONGBLOB

LONGTEXT

MEDIUMBLOB

MEDIUMINT

MEDIUMTEXTSETDATA TYPESMALLINT

TEXTTIMETIMESTAMPTINYBLOBTINYINTTINYTEXTVARBINARY

VARCHAR

YEARDATA 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> ? intName:'INT'Description:INT[(M)] [UNSIGNED] [ZEROFILL]A normal-size integer. The signed range is -2147483648 to 2147483647.

The unsigned rangeis 0 to 4294967295.

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

查看函数

mysql>? functions

You askedforhelp about help category: "Functions"For more information, type 'help ', where is one ofthe following

categories:BitFunctions

Comparison operators

Control flow functions

DateandTime 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 andTime Functions

You askedfor help about help category: "Date andTime Functions"For more information, type 'help ', where is one ofthe following

topics:

ADDDATE

ADDTIME

CONVERT_TZ

CURDATECURRENT_DATE

CURRENT_TIME

CURRENT_TIMESTAMPCURTIME

DATEFUNCTION

DATEDIFFDATE_ADD

DATE_FORMAT

DATE_SUBDAYDAYNAME

DAYOFMONTH

DAYOFWEEK

DAYOFYEAR

EXTRACT

FROM_DAYS

FROM_UNIXTIME

GET_FORMAT

HOUR

LAST_DAY

LOCALTIME

LOCALTIMESTAMP

MAKEDATE

MAKETIME

MICROSECOND

MINUTEMONTHMONTHNAME

NOW

PERIOD_ADD

PERIOD_DIFF

QUARTER

SECOND

SEC_TO_TIME

STR_TO_DATE

SUBDATE

SUBTIME

SYSDATE

TIMEFUNCTIONTIMEDIFFTIMESTAMP FUNCTIONTIMESTAMPADD

TIMESTAMPDIFF

TIME_FORMAT

TIME_TO_SEC

TO_DAYS

TO_SECONDS

UNIX_TIMESTAMP

UTC_DATE

UTC_TIME

UTC_TIMESTAMP

WEEK

WEEKDAY

WEEKOFYEARYEARYEARWEEK

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,orstatus 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]

SHOWCHARACTER SET [like_or_where]SHOW COLLATION[like_or_where]SHOW[FULL] COLUMNS FROM tbl_name [FROM db_name] [like_or_where]SHOW CONTRIBUTORS

SHOWCREATE DATABASE db_nameSHOWCREATEEVENT event_name

SHOWCREATE FUNCTIONfunc_name

SHOWCREATE PROCEDUREproc_name

SHOWCREATE TABLEtbl_name

SHOWCREATE TRIGGERtrigger_name

SHOWCREATE VIEWview_name

SHOW DATABASES[like_or_where]SHOW ENGINE engine_name {STATUS|MUTEX}

SHOW[STORAGE]ENGINES

SHOW ERRORS[LIMIT [offset,]row_count]

SHOW EVENTS

SHOWFUNCTIONCODE func_name

SHOWFUNCTION STATUS [like_or_where]SHOW GRANTSFOR userSHOWINDEX FROM tbl_name [FROM db_name]SHOW MASTER STATUS

SHOWOPEN TABLES [FROM db_name] [like_or_where]SHOW PLUGINS

SHOWPROCEDURECODE proc_name

SHOWPROCEDURE STATUS [like_or_where]SHOWPRIVILEGESSHOW[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]SHOWTABLE 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'

| WHEREexprIf 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 patternis useful forrestricting statement

outputto matching values.

Several SHOW statements also accept aWHEREclause that provides more

flexibilityin specifying which rows todisplay. 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 fromconcatenating the arguments. May

have oneor more arguments. If allarguments are nonbinary strings, the

resultis a nonbinary string. If the arguments include any binarystrings, the resultis a binary string. A numeric argument isconvertedto its equivalent string form. This is a nonbinary string as ofMySQL5.5.3. Before 5.5.3, it is a binary string; to to avoid that andproduce a nonbinary string, you canuse an explicit type cast, as inthis 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');-> NULLmysql> 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 tableName:'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_statementOr:CREATE [TEMPORARY] TABLE [IF NOT EXISTS]tbl_name

{LIKE old_tbl_name | (LIKEold_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> ? grantName:'GRANT'Description:

Syntax:GRANTpriv_type[(column_list)]

[, priv_type [(column_list)]] ...ON [object_type]priv_levelTO user_specification [, user_specification]...[REQUIRE {NONE | ssl_option [[AND]ssl_option] ...}][WITH with_option ...]

GRANT PROXY ONuser_specificationTO 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.