高效查看MySQL帮助文档的方法 （转）

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:

1. mysql> ? contents
2. You asked for help about help category: "Contents"
3. For more information, type 'help <item>', where <item> is one of the following
4. categories:
5. Account Management
6. Administration
7. Compound Statements
8. Data Definition
9. Data Manipulation
10. Data Types
11. Functions
12. Functions and Modifiers for Use with GROUP BY
13. Geographic Features
14. Help Metadata
15. Language Structure
16. Plugins
17. Procedures
18. Storage Engines
19. Table Maintenance
20. Transactions
21. User-Defined Functions
22. 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:

1. mysql> ? data types
2. You asked for help about help category: "Data Types"
3. For more information, type 'help <item>', where <item> is one of the following
4. topics:
5. AUTO_INCREMENT
6. BIGINT
7. BINARY
8. BIT
9. BLOB
10. BLOB DATA TYPE
11. BOOLEAN
12. CHAR
13. CHAR BYTE
14. DATE
15. DATETIME
16. DEC
17. DECIMAL
18. DOUBLE
19. DOUBLE PRECISION
20. ENUM
21. FLOAT
22. INT
23. INTEGER
24. LONGBLOB
25. LONGTEXT
26. MEDIUMBLOB
27. MEDIUMINT
28. MEDIUMTEXT
29. SET DATA TYPE
30. SMALLINT
31. TEXT
32. TIME
33. TIMESTAMP
34. TINYBLOB
35. TINYINT
36. TINYTEXT
37. VARBINARY
38. VARCHAR
39. 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:

1. mysql> ? int
2. Name: 'INT'
3. Description:
4. INT[(M)] [UNSIGNED] [ZEROFILL]
5. A normal-size integer. The signed range is -2147483648 to 2147483647.
6. The unsigned range is 0 to 4294967295.
7. 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

1. mysql> ? functions
2. You asked for help about help category: "Functions"
3. For more information, type 'help <item>', where <item> is one of the following
4. categories:
5. Bit Functions
6. Comparison operators
7. Control flow functions
8. Date and Time Functions
9. Encryption Functions
10. Information Functions
11. Logical operators
12. Miscellaneous Functions
13. Numeric Functions
14. 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

1. mysql> ? Date and Time Functions
2. You asked for help about help category: "Date and Time Functions"
3. For more information, type 'help <item>', where <item> is one of the following
4. topics:
5. ADDDATE
6. ADDTIME
7. CONVERT_TZ
8. CURDATE
9. CURRENT_DATE
10. CURRENT_TIME
11. CURRENT_TIMESTAMP
12. CURTIME
13. DATE FUNCTION
14. DATEDIFF
15. DATE_ADD
16. DATE_FORMAT
17. DATE_SUB
18. DAY
19. DAYNAME
20. DAYOFMONTH
21. DAYOFWEEK
22. DAYOFYEAR
23. EXTRACT
24. FROM_DAYS
25. FROM_UNIXTIME
26. GET_FORMAT
27. HOUR
28. LAST_DAY
29. LOCALTIME
30. LOCALTIMESTAMP
31. MAKEDATE
32. MAKETIME
33. MICROSECOND
34. MINUTE
35. MONTH
36. MONTHNAME
37. NOW
38. PERIOD_ADD
39. PERIOD_DIFF
40. QUARTER
41. SECOND
42. SEC_TO_TIME
43. STR_TO_DATE
44. SUBDATE
45. SUBTIME
46. SYSDATE
47. TIME FUNCTION
48. TIMEDIFF
49. TIMESTAMP FUNCTION
50. TIMESTAMPADD
51. TIMESTAMPDIFF
52. TIME_FORMAT
53. TIME_TO_SEC
54. TO_DAYS
55. TO_SECONDS
56. UNIX_TIMESTAMP
57. UTC_DATE
58. UTC_TIME
59. UTC_TIMESTAMP
60. WEEK
61. WEEKDAY
62. WEEKOFYEAR
63. YEAR
64. 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:

1. mysql> ? show
2. Name: 'SHOW'
3. Description:
4. SHOW has many forms that provide information about databases, tables,
5. columns, or status information about the server. This section describes
6. those following:
7. SHOW AUTHORS
8. SHOW {BINARY | MASTER} LOGS
9. SHOW BINLOG EVENTS [IN 'log_name'] [FROM pos] [LIMIT [offset,] row_count]
10. SHOW CHARACTER SET [like_or_where]
11. SHOW COLLATION [like_or_where]
12. SHOW [FULL] COLUMNS FROM tbl_name [FROM db_name] [like_or_where]
13. SHOW CONTRIBUTORS
14. SHOW CREATE DATABASE db_name
15. SHOW CREATE EVENT event_name
16. SHOW CREATE FUNCTION func_name
17. SHOW CREATE PROCEDURE proc_name
18. SHOW CREATE TABLE tbl_name
19. SHOW CREATE TRIGGER trigger_name
20. SHOW CREATE VIEW view_name
21. SHOW DATABASES [like_or_where]
22. SHOW ENGINE engine_name {STATUS | MUTEX}
23. SHOW [STORAGE] ENGINES
24. SHOW ERRORS [LIMIT [offset,] row_count]
25. SHOW EVENTS
26. SHOW FUNCTION CODE func_name
27. SHOW FUNCTION STATUS [like_or_where]
28. SHOW GRANTS FOR user
29. SHOW INDEX FROM tbl_name [FROM db_name]
30. SHOW MASTER STATUS
31. SHOW OPEN TABLES [FROM db_name] [like_or_where]
32. SHOW PLUGINS
33. SHOW PROCEDURE CODE proc_name
34. SHOW PROCEDURE STATUS [like_or_where]
35. SHOW PRIVILEGES
36. SHOW [FULL] PROCESSLIST
37. SHOW PROFILE [types] [FOR QUERY n] [OFFSET n] [LIMIT n]
38. SHOW PROFILES
39. SHOW SLAVE HOSTS
40. SHOW SLAVE STATUS
41. SHOW [GLOBAL | SESSION] STATUS [like_or_where]
42. SHOW TABLE STATUS [FROM db_name] [like_or_where]
43. SHOW [FULL] TABLES [FROM db_name] [like_or_where]
44. SHOW TRIGGERS [FROM db_name] [like_or_where]
45. SHOW [GLOBAL | SESSION] VARIABLES [like_or_where]
46. SHOW WARNINGS [LIMIT [offset,] row_count]
47. like_or_where:
48. LIKE 'pattern'
49. | WHERE expr
50. If the syntax for a given SHOW statement includes a LIKE 'pattern'
51. part, 'pattern' is a string that can contain the SQL "%" and "_"
52. wildcard characters. The pattern is useful for restricting statement
53. output to matching values.
54. Several SHOW statements also accept a WHERE clause that provides more
55. flexibility in specifying which rows to display. See
56. http://dev.mysql.com/doc/refman/5.5/en/extended-show.html.
57. 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

1. mysql> ? concat
2. Name: 'CONCAT'
3. Description:
4. Syntax:
5. CONCAT(str1,str2,...)
6. Returns the string that results from concatenating the arguments. May
7. have one or more arguments. If all arguments are nonbinary strings, the
8. result is a nonbinary string. If the arguments include any binary
9. strings, the result is a binary string. A numeric argument is converted
10. to its equivalent string form. This is a nonbinary string as of MySQL
11. 5.5.3. Before 5.5.3, it is a binary string; to to avoid that and
12. produce a nonbinary string, you can use an explicit type cast, as in
13. this example:
14. SELECT CONCAT(CAST(int_col AS CHAR), char_col);
15. CONCAT() returns NULL if any argument is NULL.
16. URL: http://dev.mysql.com/doc/refman/5.5/en/string-functions.html
17. Examples:
18. mysql> SELECT CONCAT('My', 'S', 'QL');
19. -> 'MySQL'
20. mysql> SELECT CONCAT('My', NULL, 'QL');
21. -> NULL
22. mysql> SELECT CONCAT(14.3);
23. -> '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:

1. mysql> ? create table
2. Name: 'CREATE TABLE'
3. Description:
4. Syntax:
5. CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
6. (create_definition,...)
7. [table_options]
8. [partition_options]
9. Or:
10. CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
11. [(create_definition,...)]
12. [table_options]
13. [partition_options]
14. select_statement
15. Or:
16. CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
17. { LIKE old_tbl_name | (LIKE old_tbl_name) }
18. ......

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

1. mysql> ? grant
2. Name: 'GRANT'
3. Description:
4. Syntax:
5. GRANT
6. priv_type [(column_list)]
7. [, priv_type [(column_list)]] ...
8. ON [object_type] priv_level
9. TO user_specification [, user_specification] ...
10. [REQUIRE {NONE | ssl_option [[AND] ssl_option] ...}]
11. [WITH with_option ...]
12. GRANT PROXY ON user_specification
13. TO user_specification [, user_specification] ...
14. [WITH GRANT OPTION]
15. object_type:
16. TABLE
17. | FUNCTION
18. | PROCEDURE
19. ......

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.