6.5.1.2 mysql Client Commands

mysql sends each SQL statement that you issue to the server to be executed. There is also a set of commands that mysql itself interprets. For a list of these commands, type help or \h at the mysql> prompt:

mysql> help

List of all MySQL commands:
Note that all text commands must be first on line and end with ';'
?         (\?) Synonym for `help'.
clear     (\c) Clear the current input statement.
connect   (\r) Reconnect to the server. Optional arguments are db and host.
delimiter (\d) Set statement 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.
resetconnection(\x) Clean session context.
query_attributes Sets string parameters (name1 value1 name2 value2 ...)
for the next query to pick up.
ssl_session_data_print Serializes the current SSL session data to stdout 
or file.

For server side help, type 'help contents'

If mysql is invoked with the --binary-mode option, all mysql commands are disabled except charset and delimiter in noninteractive mode (for input piped to mysql or loaded using the source command).

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 multiple-line /* ... */ comments is not supported. Short-form commands do work within single-line /*! ... */ version comments, as do /*+ ... */ optimizer-hint comments, which are stored in object definitions. If there is a concern that optimizer-hint comments may be stored in object definitions so that dump files when reloaded with mysql would result in execution of such commands, either invoke mysql with the --binary-mode option or use a reload client other than mysql.

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

  Display 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 6.5.1.4, “mysql Client Server-Side Help”.

• charset charset_name, \C charset_name

  Change the default character set and issue 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.

• clear, \c

  Clear 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]]

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

  If the connect command specifies a host name argument, that host takes precedence over any --dns-srv-name option given at mysql startup to specify a DNS SRV record.

• delimiter str, \d str

  Change the string that mysql interprets as the separator between SQL statements. The default is the semicolon character (;).

  The delimiter string can be specified as an unquoted or quoted argument on the delimiter command line. Quoting can be done with either single quote ('), double quote ("), or backtick (`) characters. To include a quote within a quoted string, either quote the string with a different quote character or escape the quote with a backslash (\) character. Backslash should be avoided outside of quoted strings because it is the escape character for MySQL. For an unquoted argument, the delimiter is read up to the first space or end of line. For a quoted argument, the delimiter is read up to the matching quote on the line.

  mysql interprets instances of the delimiter string as a statement delimiter anywhere it occurs, except within quoted strings. Be careful about defining a delimiter that might occur within other words. For example, if you define the delimiter as X, it is not possible to use the word INDEX in statements. mysql interprets this as INDE followed by the delimiter X.

  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 Multiple Statement Execution Support), and for parsing the body of stored procedures and functions, triggers, and events (see Section 27.1, “Defining Stored Programs”).

• edit, \e

  Edit 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

  Send the current statement to the server to be executed and display the result using vertical format.

• exit, \q

  Exit mysql.

• go, \g

  Send the current statement to the server to be executed.

• nopager, \n

  Disable output paging. See the description for pager.

  The nopager command works only in Unix.

• notee, \t

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

• nowarning, \w

  Disable display of warnings after each statement.

• pager [command], \P [command]

  Enable output paging. 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. Pager functionality works only in interactive mode.

  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

  Print the current input statement without executing it.

• prompt [str], \R [str]

  Reconfigure 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>.

• query_attributes name value [name value ...]

  Define query attributes that apply to the next query sent to the server. For discussion of the purpose and use of query attributes, see Section 11.6, “Query Attributes”.

  The query_attributes command follows these rules:

  • The format and quoting rules for attribute names and values are the same as for the delimiter command.

  • The command permits up to 32 attribute name/value pairs. Names and values may be up to 1024 characters long. If a name is given without a value, an error occurs.

  • If multiple query_attributes commands are issued prior to query execution, only the last command applies. After sending the query, mysql clears the attribute set.

  • If multiple attributes are defined with the same name, attempts to retrieve the attribute value have an undefined result.

  • An attribute defined with an empty name cannot be retrieved by name.

  • If a reconnect occurs while mysql executes the query, mysql restores the attributes after reconnecting so the query can be executed again with the same attributes.

• quit, \q

  Exit mysql.

• rehash, \#

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

• resetconnection, \x

  Reset the connection to clear the session state. This includes clearing any current query attributes defined using the query_attributes command.

  Resetting a connection has effects similar to mysql_change_user() or an auto-reconnect except that the connection is not closed and reopened, and re-authentication is not done. See mysql_change_user(), and Automatic Reconnection Control.

  This example shows how resetconnection clears a value maintained in the session state:

  mysql> SELECT LAST_INSERT_ID(3);
  +-------------------+
  | LAST_INSERT_ID(3) |
  +-------------------+
  |                 3 |
  +-------------------+
  
  mysql> SELECT LAST_INSERT_ID();
  +------------------+
  | LAST_INSERT_ID() |
  +------------------+
  |                3 |
  +------------------+
  
  mysql> resetconnection;
  
  mysql> SELECT LAST_INSERT_ID();
  +------------------+
  | LAST_INSERT_ID() |
  +------------------+
  |                0 |
  +------------------+

• source file_name, \. file_name

  Read the named file and executes the statements contained therein. On Windows, specify path name separators as / or \\.

  Quote characters are taken as part of the file name itself. For best results, the name should not include space characters.

• ssl_session_data_print [file_name]

  Fetches, serializes, and optionally stores the session data of a successful connection. The optional file name and arguments may be given to specify the file to store serialized session data. If omitted, the session data is printed to stdout.

  If the MySQL session is configured for reuse, session data from the file is deserialized and supplied to the connect command to reconnect. When the session is reused successfully, the status command contains a row showing SSL session reused: true while the client remains reconnected to the server.

• status, \s

  Provide status information about the connection and the server you are using. If you are running with --safe-updates enabled, status also prints the values for the mysql variables that affect your queries.

• system command, \! command

  Execute the given command using your default command interpreter.

  In MySQL 9.1, this command is disabled by default. You can enable it by starting the client with --system-command=ON.

• 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. Tee functionality works only in interactive mode.

  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

  Use db_name as the default database.

• warnings, \W

  Enable display of warnings after each statement (if there are any).

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:

  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 file systems mounted on /dr1 and /dr2, yet still display the results onscreen using 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.

The prompt command reconfigures the default mysql> prompt. The string for defining the prompt can contain the following special sequences.

Option	Description
\C	The current connection identifier
\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
\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	Print an asterisk (*) if the current session is inside a transaction block
\t	A tab character
\U	Your full user_name@host_name account name
\u	Your user name
\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:

  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:

  $> 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 permissible prompt options and the set of special escape sequences that are recognized in option files. (The rules for escape sequences in option files are listed in Section 6.2.2.2, “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>