mysql 帮助文档使用

mysql有很完善的帮助文档，在mysql命令行下可以通过？ 或者help 加上命令可以查看改命令的帮助信息，

我们查下几个常用的help命令

 

第一层帮助信息：

 ？ contents;

 

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
   Table Maintenance
   Transactions
   User-Defined Functions
   Utility

 

再查看具体每一层的帮助信息

 

  mysql> ? Account Management;

You asked for help about help category: "Account Management"
For more information, type 'help <item>', where <item> is one of the following
topics:
   CREATE USER
   DROP USER
   GRANT
   RENAME USER
   REVOKE
   SET PASSWORD

mysql> ? Administration
You asked for help about help category: "Administration"
For more information, type 'help <item>', where <item> is one of the following
topics:
   BINLOG
   CACHE INDEX
   CHANGE MASTER TO
   DEALLOCATE PREPARE
   EXECUTE STATEMENT
   FLUSH
   FLUSH QUERY CACHE
   HELP COMMAND
   KILL
   LOAD INDEX
   PREPARE
   PURGE BINARY LOGS
   RESET
   RESET MASTER
   RESET SLAVE
   SET
   SET GLOBAL SQL_SLAVE_SKIP_COUNTER
   SET SQL_LOG_BIN
   SHOW
   SHOW AUTHORS
   SHOW BINARY LOGS
   SHOW BINLOG EVENTS
   SHOW CHARACTER SET
   SHOW COLLATION
   SHOW COLUMNS
   SHOW CONTRIBUTORS
   SHOW CREATE DATABASE
   SHOW CREATE EVENT
   SHOW CREATE FUNCTION
   SHOW CREATE PROCEDURE
   SHOW CREATE TABLE
   SHOW CREATE TRIGGER
   SHOW CREATE VIEW
   SHOW DATABASES
   SHOW ENGINE
   SHOW ENGINES
   SHOW ERRORS
   SHOW EVENTS
   SHOW FUNCTION CODE
   SHOW FUNCTION STATUS
   SHOW GRANTS
   SHOW INDEX
   SHOW MASTER STATUS
   SHOW OPEN TABLES
   SHOW PLUGINS
   SHOW PRIVILEGES
   SHOW PROCEDURE CODE
   SHOW PROCEDURE STATUS
   SHOW PROCESSLIST
   SHOW PROFILE
   SHOW PROFILES
   SHOW RELAYLOG EVENTS
   SHOW SLAVE HOSTS
   SHOW SLAVE STATUS
   SHOW STATUS
   SHOW TABLE STATUS
   SHOW TABLES
   SHOW TRIGGERS
   SHOW VARIABLES
   SHOW WARNINGS
   START SLAVE
   STOP SLAVE

mysql> ?  Compound Statements;
You asked for help about help category: "Compound Statements"
For more information, type 'help <item>', where <item> is one of the following
topics:
   BEGIN END
   CASE STATEMENT
   CLOSE
   DECLARE CONDITION
   DECLARE CURSOR
   DECLARE HANDLER
   DECLARE VARIABLE
   FETCH
   IF STATEMENT
   ITERATE
   LEAVE
   LOOP
   OPEN
   REPEAT LOOP
   RESIGNAL
   RETURN
   SELECT INTO
   SET VARIABLE
   SIGNAL
   WHILE

mysql> ? Data Definition;
You asked for help about help category: "Data Definition"
For more information, type 'help <item>', where <item> is one of the following
topics:
   ALTER DATABASE
   ALTER EVENT
   ALTER FUNCTION
   ALTER PROCEDURE
   ALTER SERVER
   ALTER TABLE
   ALTER VIEW
   CONSTRAINT
   CREATE DATABASE
   CREATE EVENT
   CREATE FUNCTION
   CREATE INDEX
   CREATE PROCEDURE
   CREATE SERVER
   CREATE TABLE
   CREATE TRIGGER
   CREATE VIEW
   DROP DATABASE
   DROP EVENT
   DROP FUNCTION
   DROP INDEX
   DROP PROCEDURE
   DROP SERVER
   DROP TABLE
   DROP TRIGGER
   DROP VIEW
   MERGE
   RENAME TABLE
   TRUNCATE TABLE

 

这里可以根据不同的分类显示每个分类下支持的mysql指令

 

  mysql> ? START SLAVE;

Name: 'START SLAVE'
Description:
Syntax:
START SLAVE [thread_type [, thread_type] ... ]
START SLAVE [SQL_THREAD] UNTIL
    MASTER_LOG_FILE = 'log_name', MASTER_LOG_POS = log_pos
START SLAVE [SQL_THREAD] UNTIL
    RELAY_LOG_FILE = 'log_name', RELAY_LOG_POS = log_pos

thread_type: IO_THREAD | SQL_THREAD

START SLAVE with no thread_type options starts both of the slave
threads. The I/O thread reads events from the master server and stores
them in the relay log. The SQL thread reads events from the relay log
and executes them. START SLAVE requires the SUPER privilege.

If START SLAVE succeeds in starting the slave threads, it returns
without any error. However, even in that case, it might be that the
slave threads start and then later stop (for example, because they do
not manage to connect to the master or read its binary log, or some
other problem). START SLAVE does not warn you about this. You must
check the slave's error log for error messages generated by the slave
threads, or check that they are running satisfactorily with SHOW SLAVE
STATUS.

URL: http://dev.mysql.com/doc/refman/5.5/en/start-slave.html


mysql> ? MERGE
Name: 'MERGE'
Description:
The MERGE storage engine, also known as the MRG_MyISAM engine, is a
collection of identical MyISAM tables that can be used as one.
"Identical" means that all tables have identical column and index
information. You cannot merge MyISAM tables in which the columns are
listed in a different order, do not have exactly the same columns, or
have the indexes in different order. However, any or all of the MyISAM
tables can be compressed with myisampack. See
http://dev.mysql.com/doc/refman/5.5/en/myisampack.html. Differences in
table options such as AVG_ROW_LENGTH, MAX_ROWS, or PACK_KEYS do not
matter.

URL: http://dev.mysql.com/doc/refman/5.5/en/merge-storage-engine.html

Examples:
mysql> CREATE TABLE t1 (
    ->    a INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    ->    message CHAR(20)) ENGINE=MyISAM
mysql> CREATE TABLE t2 (
    ->    a INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    ->    message CHAR(20)) ENGINE=MyISAM
mysql> INSERT INTO t1 (message) VALUES ('Testing'),('table'),('t1')
mysql> INSERT INTO t2 (message) VALUES ('Testing'),('table'),('t2')
mysql> CREATE TABLE total (
    ->    a INT NOT NULL AUTO_INCREMENT,
    ->    message CHAR(20), INDEX(a))
    ->    ENGINE=MERGE UNION=(t1,t2) INSERT_METHOD=LAST

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) }

create_definition:
    col_name column_definition
  | [CONSTRAINT [symbol]] PRIMARY KEY [index_type] (index_col_name,...)
      [index_option] ...
  | {INDEX|KEY} [index_name] [index_type] (index_col_name,...)
      [index_option] ...
  | [CONSTRAINT [symbol]] UNIQUE [INDEX|KEY]
      [index_name] [index_type] (index_col_name,...)
      [index_option] ...
  | {FULLTEXT|SPATIAL} [INDEX|KEY] [index_name] (index_col_name,...)
      [index_option] ...
  | [CONSTRAINT [symbol]] FOREIGN KEY
      [index_name] (index_col_name,...) reference_definition
  | CHECK (expr)

column_definition:
    data_type [NOT NULL | NULL] [DEFAULT default_value]
      [AUTO_INCREMENT] [UNIQUE [KEY] | [PRIMARY] KEY]
      [COMMENT 'string']
      [COLUMN_FORMAT {FIXED|DYNAMIC|DEFAULT}]
      [reference_definition]

data_type:
    BIT[(length)]
  | TINYINT[(length)] [UNSIGNED] [ZEROFILL]
  | SMALLINT[(length)] [UNSIGNED] [ZEROFILL]
  | MEDIUMINT[(length)] [UNSIGNED] [ZEROFILL]
  | INT[(length)] [UNSIGNED] [ZEROFILL]
  | INTEGER[(length)] [UNSIGNED] [ZEROFILL]
  | BIGINT[(length)] [UNSIGNED] [ZEROFILL]
  | REAL[(length,decimals)] [UNSIGNED] [ZEROFILL]
  | DOUBLE[(length,decimals)] [UNSIGNED] [ZEROFILL]
  | FLOAT[(length,decimals)] [UNSIGNED] [ZEROFILL]
  | DECIMAL[(length[,decimals])] [UNSIGNED] [ZEROFILL]
  | NUMERIC[(length[,decimals])] [UNSIGNED] [ZEROFILL]
  | DATE
  | TIME
  | TIMESTAMP
  | DATETIME
  | YEAR
  | CHAR[(length)]
      [CHARACTER SET charset_name] [COLLATE collation_name]
  | VARCHAR(length)
      [CHARACTER SET charset_name] [COLLATE collation_name]
  | BINARY[(length)]
  | VARBINARY(length)
  | TINYBLOB
  | BLOB
  | MEDIUMBLOB
  | LONGBLOB
  | TINYTEXT [BINARY]
      [CHARACTER SET charset_name] [COLLATE collation_name]
  | TEXT [BINARY]
      [CHARACTER SET charset_name] [COLLATE collation_name]
  | MEDIUMTEXT [BINARY]
      [CHARACTER SET charset_name] [COLLATE collation_name]
  | LONGTEXT [BINARY]
      [CHARACTER SET charset_name] [COLLATE collation_name]
  | ENUM(value1,value2,value3,...)
      [CHARACTER SET charset_name] [COLLATE collation_name]
  | SET(value1,value2,value3,...)
      [CHARACTER SET charset_name] [COLLATE collation_name]
  | spatial_type

index_col_name:
    col_name [(length)] [ASC | DESC]

index_type:
    USING {BTREE | HASH}

index_option:
    KEY_BLOCK_SIZE [=] value
  | index_type
  | WITH PARSER parser_name
  | COMMENT 'string'

reference_definition:
    REFERENCES tbl_name (index_col_name,...)
      [MATCH FULL | MATCH PARTIAL | MATCH SIMPLE]
      [ON DELETE reference_option]
      [ON UPDATE reference_option]

reference_option:
    RESTRICT | CASCADE | SET NULL | NO ACTION

table_options:
    table_option [[,] table_option] ...

table_option:
    ENGINE [=] engine_name
  | AUTO_INCREMENT [=] value
  | AVG_ROW_LENGTH [=] value
  | [DEFAULT] CHARACTER SET [=] charset_name
  | CHECKSUM [=] {0 | 1}
  | [DEFAULT] COLLATE [=] collation_name
  | COMMENT [=] 'string'
  | CONNECTION [=] 'connect_string'
  | DATA DIRECTORY [=] 'absolute path to directory'
  | DELAY_KEY_WRITE [=] {0 | 1}
  | INDEX DIRECTORY [=] 'absolute path to directory'
  | INSERT_METHOD [=] { NO | FIRST | LAST }
  | KEY_BLOCK_SIZE [=] value
  | MAX_ROWS [=] value
  | MIN_ROWS [=] value
  | PACK_KEYS [=] {0 | 1 | DEFAULT}
  | PASSWORD [=] 'string'
  | ROW_FORMAT [=] {DEFAULT|DYNAMIC|FIXED|COMPRESSED|REDUNDANT|COMPACT}
  | UNION [=] (tbl_name[,tbl_name]...)

partition_options:
    PARTITION BY
        { [LINEAR] HASH(expr)
        | [LINEAR] KEY(column_list)
        | RANGE{(expr) | COLUMNS(column_list)}
        | LIST{(expr) | COLUMNS(column_list)} }
    [PARTITIONS num]
    [SUBPARTITION BY
        { [LINEAR] HASH(expr)
        | [LINEAR] KEY(column_list) }
      [SUBPARTITIONS num]
    ]
    [(partition_definition [, partition_definition] ...)]

partition_definition:
    PARTITION partition_name
        [VALUES
            {LESS THAN {(expr | value_list) | MAXVALUE}
            |
            IN (value_list)}]
        [[STORAGE] ENGINE [=] engine_name]
        [COMMENT [=] 'comment_text' ]
        [DATA DIRECTORY [=] 'data_dir']
        [INDEX DIRECTORY [=] 'index_dir']
        [MAX_ROWS [=] max_number_of_rows]
        [MIN_ROWS [=] min_number_of_rows]
        [(subpartition_definition [, subpartition_definition] ...)]

subpartition_definition:
    SUBPARTITION logical_name
        [[STORAGE] ENGINE [=] engine_name]
        [COMMENT [=] 'comment_text' ]
        [DATA DIRECTORY [=] 'data_dir']
        [INDEX DIRECTORY [=] 'index_dir']
        [MAX_ROWS [=] max_number_of_rows]
        [MIN_ROWS [=] min_number_of_rows]

select_statement:
    [IGNORE | REPLACE] [AS] SELECT ...   (Some legal select statement)

CREATE TABLE creates a table with the given name. You must have the
CREATE privilege for the table.

Rules for permissible table names are given in
http://dev.mysql.com/doc/refman/5.5/en/identifiers.html. By default,
the table is created in the default database, using the InnoDB storage
engine. An error occurs if the table exists, if there is no default
database, or if the database does not exist.

URL: http://dev.mysql.com/doc/refman/5.5/en/create-table.html


mysql>

 

 

至于上面一层的命令，我们还可以查看mysql支持的数据类型，

 

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> ? Utility;
You asked for help about help category: "Utility"
For more information, type 'help <item>', where <item> is one of the following
topics:
   DESCRIBE
   EXPLAIN
   HELP STATEMENT
   USE

 

通过帮助文档还是很方便查到mysql的所有名称，已经每个命令的使用方法和语法。

 

可以查看mysql内置函数列表，以及每个函数的功能和使用方法：

mysql> ? Functions;
You asked for help about help category: "Functions"
For more information, type 'help <item>', where <item> is one of the following
topics:
   PROCEDURE ANALYSE
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> ? String Functions;
You asked for help about help category: "String Functions"
For more information, type 'help <item>', where <item> is one of the following
topics:
   ASCII
   BIN
   BINARY OPERATOR
   BIT_LENGTH
   CAST
   CHAR FUNCTION
   CHARACTER_LENGTH
   CHAR_LENGTH
   CONCAT
   CONCAT_WS
   CONVERT
   ELT
   EXPORT_SET
   EXTRACTVALUE
   FIELD
   FIND_IN_SET
   FORMAT
   HEX
   INSERT FUNCTION
   INSTR
   LCASE
   LEFT
   LENGTH
   LIKE
   LOAD_FILE
   LOCATE
   LOWER
   LPAD
   LTRIM
   MAKE_SET
   MATCH AGAINST
   MID
   NOT LIKE
   NOT REGEXP
   OCTET_LENGTH
   ORD
   POSITION
   QUOTE
   REGEXP
   REPEAT FUNCTION
   REPLACE FUNCTION
   REVERSE
   RIGHT
   RPAD
   RTRIM
   SOUNDEX
   SOUNDS LIKE
   SPACE
   STRCMP
   SUBSTR
   SUBSTRING
   SUBSTRING_INDEX
   TRIM
   UCASE
   UNHEX
   UPDATEXML
   UPPER

mysql> ? QUOTE;
Name: 'QUOTE'
Description:
Syntax:
QUOTE(str)

Quotes a string to produce a result that can be used as a properly
escaped data value in an SQL statement. The string is returned enclosed
by single quotation marks and with each instance of backslash ("\"),
single quote ("'"), ASCII NUL, and Control+Z preceded by a backslash.
If the argument is NULL, the return value is the word "NULL" without
enclosing single quotation marks.

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

Examples:
mysql> SELECT QUOTE('Don\'t!')
        -> 'Don\'t!'
mysql> SELECT QUOTE(NULL)
        -> NULL

mysql>

 

 

mysql的插件信息和事务之类的其他信息

 

mysql> ? Plugins;
Name: 'SHOW PLUGINS'
Description:
Syntax:
SHOW PLUGINS

SHOW PLUGINS displays information about server plugins. Plugin
information is also available in the INFORMATION_SCHEMA.PLUGINS table.
See http://dev.mysql.com/doc/refman/5.5/en/plugins-table.html.

Example of SHOW PLUGINS output:

mysql> SHOW PLUGINS\G
*************************** 1. row ***************************
   Name: binlog
 Status: ACTIVE
   Type: STORAGE ENGINE
Library: NULL
License: GPL
*************************** 2. row ***************************
   Name: CSV
 Status: ACTIVE
   Type: STORAGE ENGINE
Library: NULL
License: GPL
*************************** 3. row ***************************
   Name: MEMORY
 Status: ACTIVE
   Type: STORAGE ENGINE
Library: NULL
License: GPL
*************************** 4. row ***************************
   Name: MyISAM
 Status: ACTIVE
   Type: STORAGE ENGINE
Library: NULL
License: GPL
...

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


mysql> ? Transations;

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

mysql> ? Transactions;
You asked for help about help category: "Transactions"
For more information, type 'help <item>', where <item> is one of the following
topics:
   ISOLATION
   LOCK
   SAVEPOINT
   START TRANSACTION

mysql>

 

通过帮助文档可以查询到mysql的所有命令及每个命令的功能，语法。