Wednesday, April 1, 2009

command mysql

Note that all text commands must be first on line and end with ';'
? (\?) Synonym for `help'.
clear (\c) Clear command.
connect (\r) Reconnect to the server. Optional arguments are db and host.
delimiter (\d) Set statement delimiter. NOTE: Takes the rest of the line as
new delimiter.
edit (\e) Edit command with $EDITOR.
ego (\G) Send command to mysql server, display result vertically.
exit (\q) Exit mysql. Same as quit.
go (\g) Send command to mysql server.
help (\h) Display this help.
nopager (\n) Disable pager, print to stdout.
notee (\t) Don't write into outfile.
pager (\P) Set PAGER [to_pager]. Print the query results via PAGER.
print (\p) Print current command.
prompt (\R) Change your mysql prompt.
quit (\q) Quit mysql.
rehash (\#) Rebuild completion hash.
source (\.) Execute an SQL script file. Takes a file name as an argument.
status (\s) Get status information from the server.
system (\!) Execute a system shell command.
tee (\T) Set outfile [to_outfile]. Append everything into given
outfile.
use (\u) Use another database. Takes database name as argument.
charset (\C) Switch to another charset. Might be needed for processing
binlog with multi-byte charsets.
warnings (\W) Show warnings after every statement.
nowarning (\w) Don't show warnings after every statement.


Each command has both a long and short form. The long form is not case sensitive; the short form is. The long form can be followed by an optional semicolon terminator, but the short form should not.

The use of short-form commands within multi-line /* ... */ comments is not supported.

help [arg], \h [arg], \? [arg], ? [arg]


Displays a help message listing the available mysql commands.

If you provide an argument to the help command, mysql uses it as a search string to access server-side help from the contents of the MySQL Reference Manual. For more information, see Section 4.5.1.3, “mysql Server-Side Help”.

charset charset_name, \C charset_name

The charset command changes the default character set and issues a SET NAMES statement. This enables the character set to remain synchronized on the client and server if mysql is run with auto-reconnect enabled (which is not recommended), because the specified character set is used for reconnects. This command was added in MySQL 5.0.19.

clear, \c

Clears the current input. Use this if you change your mind about executing the statement that you are entering.

connect [db_name host_name]], \r [db_name host_name]]

Reconnects to the server. The optional database name and hostname arguments may be given to specify the default database or the host where the server is running. If omitted, the current values are used.

delimiter str, \d str

The delimiter command changes the string that mysql interprets as the separator between SQL statements. The default is the semicolon character (“;”). You should avoid the use of the backslash (“\”) character within the delimiter because that is the escape character for MySQL.

When the delimiter recognized by mysql is set to something other than the default of “;”, instances of that character are sent to the server without interpretation. However, the server itself still interprets “;” as a statement delimiter and processes statements accordingly. This behavior on the server side comes into play for multiple-statement execution (see Section 24.7.9, “C API Handling of Multiple Statement Execution”), and for parsing the body of stored procedures and functions and triggers (see Section 12.1.8, “CREATE PROCEDURE and CREATE FUNCTION Syntax”).

edit, \e

Edits the current input statement. mysql checks the values of the EDITOR and VISUAL environment variables to determine which editor to use. The default editor is vi if neither variable is set.

The edit command works only in Unix.

ego, \G

Sends the current statement to the server to be executed and displays the result using vertical format.

exit, \q

Exits mysql.

go, \g

Sends the current statement to the server to be executed.

nopager, \n

Disables output paging. See the description for pager.

The nopager command works only in Unix.

notee, \t

Disables output copying to the tee file. See the description for tee.

nowarning, \w

Enables display of warnings after each statement. This command was added in MySQL 5.0.6.

pager [command], \P [command]

By using the --pager option when you invoke mysql, it is possible to browse or search query results in interactive mode with Unix programs such as less, more, or any other similar program. If you specify no value for the option, mysql checks the value of the PAGER environment variable and sets the pager to that.

Output paging can be enabled interactively with the pager command and disabled with nopager. The command takes an optional argument; if given, the paging program is set to that. With no argument, the pager is set to the pager that was set on the command line, or stdout if no pager was specified.

Output paging works only in Unix because it uses the popen() function, which does not exist on Windows. For Windows, the tee option can be used instead to save query output, although it is not as convenient as pager for browsing output in some situations.

print, \p

Prints the current input statement without executing it.

prompt [str], \R [str]

Reconfigures the mysql prompt to the given string. The special character sequences that can be used in the prompt are described later in this section.

If you specify the prompt command with no argument, mysql resets the prompt to the default of mysql>.

quit, \q

Exits mysql.

rehash, \#

Rebuilds the completion hash that enables database, table, and column name completion while you are entering statements. (See the description for the --auto-rehash option.)

source file_name, \. file_name

Reads the named file and executes the statements contained therein. On Windows, you can specify pathname separators as / or \\.

status, \s

The status command provides some information about the connection and the server you are using. If you are running in --safe-updates mode, status also prints the values for the mysql variables that affect your queries.

system command, \! command

Executes the given command using your default command interpreter.

The system command works only in Unix.

tee [file_name], \T [file_name]

By using the --tee option when you invoke mysql, you can log statements and their output. All the data displayed on the screen is appended into a given file. This can be very useful for debugging purposes also. mysql flushes results to the file after each statement, just before it prints its next prompt.

You can enable this feature interactively with the tee command. Without a parameter, the previous file is used. The tee file can be disabled with the notee command. Executing tee again re-enables logging.

use db_name, \u db_name

Uses db_name as the default database.

warnings, \W

Enables display of warnings after each statement (if there are any). This command was added in MySQL 5.0.6.

Here are a few tips about the pager command:

You can use it to write to a file and the results go only to the file:

mysql> pager cat > /tmp/log.txt
You can also pass any options for the program that you want to use as your pager:

mysql> pager less -n -i -S
In the preceding example, note the -S option. You may find it very useful for browsing wide query results. Sometimes a very wide result set is difficult to read on the screen. The -S option to less can make the result set much more readable because you can scroll it horizontally using the left-arrow and right-arrow keys. You can also use -S interactively within less to switch the horizontal-browse mode on and off. For more information, read the less manual page:

shell> man less
The -F and -X options may be used with less to cause it to exit if output fits on one screen, which is convenient when no scrolling is necessary:

mysql> pager less -n -i -S -F -X
You can specify very complex pager commands for handling query output:

mysql> pager cat | tee /dr1/tmp/res.txt \
| tee /dr2/tmp/res2.txt | less -n -i -S
In this example, the command would send query results to two files in two different directories on two different filesystems mounted on /dr1 and /dr2, yet still display the results onscreen via less.

You can also combine the tee and pager functions. Have a tee file enabled and pager set to less, and you are able to browse the results using the less program and still have everything appended into a file the same time. The difference between the Unix tee used with the pager command and the mysql built-in tee command is that the built-in tee works even if you do not have the Unix tee available. The built-in tee also logs everything that is printed on the screen, whereas the Unix tee used with pager does not log quite that much. Additionally, tee file logging can be turned on and off interactively from within mysql. This is useful when you want to log some queries to a file, but not others.



\c A counter that increments for each statement you issue
\D The full current date
\d The default database
\h The server host
\l The current delimiter (new in 5.0.25)
\m Minutes of the current time
\n A newline character
\O The current month in three-letter format (Jan, Feb, …)
\o The current month in numeric format
\P am/pm
\p The current TCP/IP port or socket file
\R The current time, in 24-hour military time (0-23)
\r The current time, standard 12-hour time (1-12)
\S Semicolon
\s Seconds of the current time
\t A tab character
\U Your full user_name@host_name account name
\u Your username
\v The server version
\w The current day of the week in three-letter format (Mon, Tue, …)
\Y The current year, four digits
\y The current year, two digits
\_ A space
\ A space (a space follows the backslash)
\' Single quote
\" Double quote
\\ A literal “\” backslash character
\x x, for any “x” not listed above

You can set the prompt in several ways:

Use an environment variable. You can set the MYSQL_PS1 environment variable to a prompt string. For example:

shell> export MYSQL_PS1="(\u@\h) [\d]> "
Use a command-line option. You can set the --prompt option on the command line to mysql. For example:

shell> mysql --prompt="(\u@\h) [\d]> "
(user@host) [database]>
Use an option file. You can set the prompt option in the [mysql] group of any MySQL option file, such as /etc/my.cnf or the .my.cnf file in your home directory. For example:

[mysql]
prompt=(\\u@\\h) [\\d]>\\_
In this example, note that the backslashes are doubled. If you set the prompt using the prompt option in an option file, it is advisable to double the backslashes when using the special prompt options. There is some overlap in the set of allowable prompt options and the set of special escape sequences that are recognized in option files. (These sequences are listed in Section 4.2.3.2, “Using Option Files”.) The overlap may cause you problems if you use single backslashes. For example, \s is interpreted as a space rather than as the current seconds value. The following example shows how to define a prompt within an option file to include the current time in HH:MM:SS> format:

[mysql]
prompt="\\r:\\m:\\s> "
Set the prompt interactively. You can change your prompt interactively by using the prompt (or \R) command. For example:

mysql> prompt (\u@\h) [\d]>\_
PROMPT set to '(\u@\h) [\d]>\_'
(user@host) [database]>
(user@host) [database]> prompt
Returning to default PROMPT of mysql>
mysql>

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