mysql



MYSQL(1)                     MySQL Database System                    MYSQL(1)




NAME

       mysql - the MySQL command-line tool


SYNOPSIS

       mysql [options] db_name


DESCRIPTION

       mysql is a simple SQL shell (with GNU readline capabilities). It
       supports interactive and non-interactive use. When used interactively,
       query results are presented in an ASCII-table format. When used
       non-interactively (for example, as a filter), the result is presented
       in tab-separated format. The output format can be changed using
       command-line options.

       If you have problems due to insufficient memory for large result sets,
       use the --quick option. This forces mysql to retrieve results from the
       server a row at a time rather than retrieving the entire result set and
       buffering it in memory before displaying it. This is done by using
       mysql_use_result() rather than mysql_store_result() to retrieve the
       result set.

       Using mysql is very easy. Invoke it from the prompt of your command
       interpreter as follows:

       shell> mysql db_name

       Or:

       shell> mysql --user=user_name --password=your_password db_name

       Then type an SQL statement, end it with ‘;’, \g, or \G and press Enter.

       You can run a script simply like this:

       shell> mysql db_name < script.sql > output.tab


OPTIONS

       mysql supports the following options:

       ·  --help, -?

          Display a help message and exit.

       ·  --batch, -B

          Print results using tab as the column separator, with each row on a
          new line. With this option, mysql does not use the history file.

       ·  --character-sets-dir=path

          The directory where character sets are installed. See Section 7.1,
          “The Character Set Used for Data and Sorting”.

       ·  --compress, -C

          Compress all information sent between the client and the server if
          both support compression.

       ·  --database=db_name, -D db_name

          The database to use. This is useful mainly in an option file.

       ·  --debug[=debug_options], -# [debug_options]

          Write a debugging log. The debug_options string often is
          ´d:t:o,file_name’. The default is ´d:t:o,/tmp/mysql.trace’.

       ·  --debug-info, -T

          Print some debugging information when the program exits.

       ·  --default-character-set=charset

          Use charset as the default character set. See Section 7.1, “The
          Character Set Used for Data and Sorting”.

       ·  --execute=statement, -e statement

          Execute the statement and quit. The default output format is like
          that produced with --batch. See Section 3.1, “Using Options on the
          Command Line” for some examples.

       ·  --force, -f

          Continue even if an SQL error occurs.

       ·  --host=host_name, -h host_name

          Connect to the MySQL server on the given host.

       ·  --html, -H

          Produce HTML output.

       ·  --ignore-space, -i

          Ignore spaces after function names. The effect of this is described
          in the discussion for IGNORE_SPACE in the section called “THE SERVER
          SQL MODE”.

       ·  --local-infile[={0|1}]

          Enable or disable LOCAL capability for LOAD DATA INFILE. With no
          value, the option enables LOCAL. It may be given as --local-infile=0
          or --local-infile=1 to explicitly disable or enable LOCAL. Enabling
          LOCAL has no effect if the server does not also support it.

       ·  --named-commands, -G

          Named commands are enabled. Long format commands are allowed as well
          as shortened \* commands. For example, quit and \q both are
          recognized.

       ·  --no-auto-rehash, -A

          No automatic rehashing. This option causes mysql to start faster,
          but you must issue the rehash command if you want to use table and
          column name completion.

       ·  --no-beep, -b

          Do not beep when errors occur.

       ·  --no-named-commands, -g

          Named commands are disabled. Use the \* form only, or use named
          commands only at the beginning of a line ending with a semicolon
          (‘;’). As of MySQL 3.23.22, mysql starts with this option enabled by
          default. However, even with this option, long-format commands still
          work from the first line.

       ·  --no-pager

          Do not use a pager for displaying query output. Output paging is
          discussed further in the section called “\FBMYSQL\FR COMMANDS”.

       ·  --no-tee

          Do not copy output to a file. Tee files are discussed further in the
          section called “\FBMYSQL\FR COMMANDS”.

       ·  --one-database, -O

          Ignore statements except those for the default database named on the
          command line. This is useful for skipping updates to other databases
          in the binary log.

       ·  --pager[=command]

          Use the given command for paging query output. If the command is
          omitted, the default pager is the value of your PAGER environment
          variable. Valid pagers are less, more, cat [> filename], and so
          forth. This option works only on Unix. It does not work in batch
          mode. Output paging is discussed further in the section called
          “\FBMYSQL\FR COMMANDS”.

       ·  --password[=password], -p[password]

          The password to use when connecting to the server. If you use the
          short option form (-p), you cannot have a space between the option
          and the password. If you omit the password value following the
          --password or -p option on the command line, you are prompted for
          one. The password should be omitted on SysV-based UNIX systems, as
          the password may be displayed in the output of ps.

       ·  --port=port_num, -P port_num

          The TCP/IP port number to use for the connection.

       ·  --prompt=format_str

          Set the prompt to the specified format. The default is mysql>. The
          special sequences that the prompt can contain are described in the
          section called “\FBMYSQL\FR COMMANDS”.

       ·  --protocol={TCP | SOCKET | PIPE | MEMORY}

          The connection protocol to use. Added in MySQL 4.1.

       ·  --quick, -q

          Do not cache each query result, print each row as it is received.
          This may slow down the server if the output is suspended. With this
          option, mysql does not use the history file.

       ·  --raw, -r

          Write column values without escape conversion. Often used with the
          --batch option.

       ·  --reconnect

          If the connection to the server is lost, automatically try to
          reconnect. A single reconnect attempt is made each time the
          connection is lost. To suppress reconnection behavior, use
          --skip-reconnect. Added in MySQL 4.1.0.

       ·  --safe-updates, --i-am-a-dummy, -U

          Allow only those UPDATE and DELETE statements that specify rows to
          affect using key values. If you have set this option in an option
          file, you can override it by using --safe-updates on the command
          line. See the section called “\FBMYSQL\FR TIPS” for more information
          about this option.

       ·  --secure-auth

          Do not send passwords to the server in old (pre-4.1.1) format. This
          prevents connections except for servers that use the newer password
          format. This option was added in MySQL 4.1.1.

       ·  --sigint-ignore

          Ignore SIGINT signals (typically the result of typing Control-C).
          This option was added in MySQL 4.1.6.

       ·  --silent, -s

          Silent mode. Produce less output. This option can be given multiple
          times to produce less and less output.

       ·  --skip-column-names, -N

          Do not write column names in results.

       ·  --skip-line-numbers, -L

          Do not write line numbers for errors. Useful when you want to
          compare result files that include error messages.

       ·  --socket=path, -S path

          The socket file to use for the connection.

       ·  --table, -t

          Display output in table format. This is the default for interactive
          use, but can be used to produce table output in batch mode.

       ·  --tee=file_name

          Append a copy of output to the given file. This option does not work
          in batch mode. Tee files are discussed further in the section called
          “\FBMYSQL\FR COMMANDS”.

       ·  --unbuffered, -n

          Flush the buffer after each query.

       ·  --user=user_name, -u user_name

          The MySQL username to use when connecting to the server.

       ·  --verbose, -v

          Verbose mode. Produce more output. This option can be given multiple
          times to produce more and more output. (For example, -v -v -v
          produces the table output format even in batch mode.)

       ·  --version, -V

          Display version information and exit.

       ·  --vertical, -E

          Print the rows of query output vertically. Without this option, you
          can specify vertical output for individual statements by terminating
          them with \G.

       ·  --wait, -w

          If the connection cannot be established, wait and retry instead of
          aborting.

       ·  --xml, -X

          Produce XML output.

       You can also set the following variables by using --var_name=value
       options:

       ·  connect_timeout

          The number of seconds before connection timeout. (Default value is
          0.)

       ·  max_allowed_packet

          The maximum packet length to send to or receive from the server.
          (Default value is 16MB.)

       ·  max_join_size

          The automatic limit for rows in a join when using --safe-updates.
          (Default value is 1,000,000.)

       ·  net_buffer_length

          The buffer size for TCP/IP and socket communication. (Default value
          is 16KB.)

       ·  select_limit

          The automatic limit for SELECT statements when using --safe-updates.
          (Default value is 1,000.)

       It is also possible to set variables by using
       --set-variable=var_name=value or -O var_name=value syntax. In MySQL
       4.1, this syntax is deprecated.

       On Unix, the mysql client writes a record of executed statements to a
       history file. By default, the history file is named .mysql_history and
       is created in your home directory. To specify a different file, set the
       value of the MYSQL_HISTFILE environment variable.

       If you do not want to maintain a history file, first remove
       .mysql_history if it exists, and then use either of the following
       techniques:

       ·  Set the MYSQL_HISTFILE variable to /dev/null. To cause this setting
          to take effect each time you log in, put the setting in one of your
          shell’s startup files.

       ·  Create .mysql_history as a symbolic link to /dev/null:

          shell> ln -s /dev/null $HOME/.mysql_history
          You need do this only once.


MYSQL COMMANDS

       mysql sends SQL statements 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
       MySQL commands:
       ?         (\?) 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 a 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.
       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.

       In the delimiter command, you should avoid the use of the backslash
       (‘\’) character because that is the escape character for MySQL.

       The edit, nopager, pager, and system commands work only in Unix.

       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.

       To log queries and their output, use the tee command. All the data
       displayed on the screen is appended into a given file. This can be very
       useful for debugging purposes also. You can enable this feature on the
       command line with the --tee option, or interactively with the tee
       command. The tee file can be disabled interactively with the notee
       command. Executing tee again re-enables logging. Without a parameter,
       the previous file is used. Note that tee flushes query results to the
       file after each statement, just before mysql prints its next prompt.

       Browsing or searching query results in interactive mode by using Unix
       programs such as less, more, or any other similar program is possible
       with the --pager option. 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 this is not as convenient
       as pager for browsing output in some situations.

       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

       ·  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.

       From MySQL 4.0.2 on, the default mysql> prompt can be reconfigured. The
       string for defining the prompt can contain the following special
       sequences: OptionDescription\vThe server version\dThe current
       database\hThe server host\pThe current TCP/IP port or socket file\uYour
       username\UYour full
                         user_name@host_name
                         account name\\A literal ‘\’ backslash character\nA
       newline character\tA tab character\ A space (a space follows the
       backslash)\_A space\RThe current time, in 24-hour military time
       (0-23)\rThe current time, standard 12-hour time (1-12)\mMinutes of the
       current time\yThe current year, two digits\YThe current year, four
       digits\DThe full current date\sSeconds of the current time\wThe current
       day of the week in three-letter format (Mon, Tue, ...)\Pam/pm\oThe
       current month in numeric format\OThe current month in three-letter
       format (Jan, Feb, ...)\cA counter that increments for each statement
       you issue\SSemicolon\’Single quote\"Double quote.PP ‘\’ followed by any
       other letter just becomes that letter.

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

       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 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 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> "

       ·  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]>

       ·  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>


EXECUTING SQL STATEMENTS FROM A TEXT FILE

       The mysql client typically is used interactively, like this:

       shell> mysql db_name

       However, it is also possible to put your SQL statements in a file and
       then tell mysql to read its input from that file. To do so, create a
       text file text_file that contains the statements you wish to execute.
       Then invoke mysql as shown here:

       shell> mysql db_name < text_file

       You can also start your text file with a USE db_name statement. In this
       case, it is unnecessary to specify the database name on the command
       line:

       shell> mysql < text_file

       If you are running mysql, you can execute an SQL script file using the
       source or \.  command:

       mysql> source filename
       mysql> \. filename

       Sometimes you may want your script to display progress information to
       the user; for this you can insert some lines like

       SELECT ’<info_to_display>’ AS ’ ’;

       which outputs <info_to_display>.

       For more information about batch mode, see Section 5, “Using mysql in
       Batch Mode”.


MYSQL TIPS

       This section describes some techniques that can help you use mysql more
       effectively.

   Displaying Query Results Vertically
       Some query results are much more readable when displayed vertically,
       instead of in the usual horizontal table format. Queries can be
       displayed vertically by terminating the query with \G instead of a
       semicolon. For example, longer text values that include newlines often
       are much easier to read with vertical output:

       mysql> SELECT * FROM mails WHERE LENGTH(txt) < 300 LIMIT 300,1\G
       *************************** 1. row ***************************
         msg_nro: 3068
            date: 2000-03-01 23:29:50
       time_zone: +0200
       mail_from: Monty
           reply: monty@no.spam.com
         mail_to: "Thimble Smith" <tim@no.spam.com>
             sbj: UTF-8
             txt: >>>>> "Thimble" == Thimble Smith writes:
       Thimble> Hi.  I think this is a good idea.  Is anyone familiar
       Thimble> with UTF-8 or Unicode? Otherwise, I’ll put this on my
       Thimble> TODO list and see what happens.
       Yes, please do that.
       Regards,
       Monty
            file: inbox-jani-1
            hash: 190402944
       1 row in set (0.09 sec)

   Using the --safe-updates Option
       For beginners, a useful startup option is --safe-updates (or
       --i-am-a-dummy, which has the same effect). This option was introduced
       in MySQL 3.23.11. It is helpful for cases when you might have issued a
       DELETE FROM tbl_name statement but forgotten the WHERE clause.
       Normally, such a statement deletes all rows from the table. With
       --safe-updates, you can delete rows only by specifying the key values
       that identify them. This helps prevent accidents.

       When you use the --safe-updates option, mysql issues the following
       statement when it connects to the MySQL server:

       SET SQL_SAFE_UPDATES=1,SQL_SELECT_LIMIT=1000, SQL_MAX_JOIN_SIZE=1000000;

       See Section 5.3, “SET Syntax”.

       The SET statement has the following effects:

       ·  You are not allowed to execute an UPDATE or DELETE statement unless
          you specify a key constraint in the WHERE clause or provide a LIMIT
          clause (or both). For example:

          UPDATE tbl_name SET not_key_column=val WHERE key_column=val;
          UPDATE tbl_name SET not_key_column=val LIMIT 1;

       ·  All large SELECT results are automatically limited to 1,000 rows
          unless the statement includes a LIMIT clause.

       ·  Multiple-table SELECT statements that probably need to examine more
          than 1,000,000 row combinations are aborted.

       To specify limits other than 1,000 and 1,000,000, you can override the
       defaults by using --select_limit and --max_join_size options:

       shell> mysql --safe-updates --select_limit=500 --max_join_size=10000

   Disabling mysql Auto-Reconnect
       If the mysql client loses its connection to the server while sending a
       query, it immediately and automatically tries to reconnect once to the
       server and send the query again. However, even if mysql succeeds in
       reconnecting, your first connection has ended and all your previous
       session objects and settings are lost: temporary tables, the autocommit
       mode, and user and session variables. This behavior may be dangerous
       for you, as in the following example where the server was shut down and
       restarted without you knowing it:

       mysql> SET @a=1;
       Query OK, 0 rows affected (0.05 sec)
       mysql> INSERT INTO t VALUES(@a);
       ERROR 2006: MySQL server has gone away
       No connection. Trying to reconnect...
       Connection id:    1
       Current database: test
       Query OK, 1 row affected (1.30 sec)
       mysql> SELECT * FROM t;
       +------+
       | a    |
       +------+
       | NULL |
       +------+
       1 row in set (0.05 sec)

       The @a user variable has been lost with the connection, and after the
       reconnection it is undefined. If it is important to have mysql
       terminate with an error if the connection has been lost, you can start
       the mysql client with the --skip-reconnect option.


SEE ALSO

       isamchk(1), isamlog(1), msql2mysql(1), myisamchk(1), myisamlog(1),
       myisampack(1), mysql.server(1), mysql_config(1),
       mysql_fix_privilege_tables(1), mysql_zap(1), mysqlaccess(1),
       mysqladmin(1), mysqlbinlog(1), mysqlcheck(1), mysqld(1),
       mysqld_multi(1), mysqld_safe(1), mysqldump(1), mysqlhotcopy(1),
       mysqlimport(1), mysqlshow(1), pack_isam(1), perror(1), replace(1),
       safe_mysqld(1)

       For more information, please refer to the MySQL Reference Manual, which
       may already be installed locally and which is also available online at
       http://dev.mysql.com/doc/.


AUTHOR

       MySQL AB (http://www.mysql.com/).  This software comes with no
       warranty.



MySQL 4.1                         11/30/2005                          MYSQL(1)

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