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mysql(1)                     MySQL Database System                    mysql(1)


       mysql - the MySQL command-line tool


       mysql [options] db_name


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

       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 returning
       the result set using the mysql_use_result() C API function in the
       client/server library rather than mysql_store_result().

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

           shell> mysql db_name


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

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

       As of MySQL 5.0.25, typing Control-C causes mysql to attempt to kill
       the current statement. If this cannot be done, or Control-C is typed
       again before the statement is killed, mysql exits. Previously,
       Control-C caused mysql to exit in all cases.

       You can execute SQL statements in a script file (batch file) like this:

           shell> mysql db_name < script.sql >


       mysql supports the options in the following list. It also reads option
       files and supports the options for processing them described at
       Section, "Command-Line Options that Affect Option-File

       o   --help, -?

           Display a help message and exit.

       o   --auto-rehash

           Enable automatic rehashing. This option is on by default, which
           enables database, table, and column name completion. Use
           --disable-auto-rehash to disable rehashing. That causes mysql to
           start faster, but you must issue the rehash command if you want to
           use name completion.

           To complete a name, enter the first part and press Tab. If the name
           is unambiguous, mysql completes it. Otherwise, you can press Tab
           again to see the possible names that begin with what you have typed
           so far. Completion does not occur if there is no default database.

       o   --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.

           Batch mode results in nontabular output format and escaping of
           special characters. Escaping may be disabled by using raw mode; see
           the description for the --raw option.

       o   --character-sets-dir=path

           The directory where character sets are installed. See Section 9.2,
           "The Character Set Used for Data and Sorting".

       o   --column-names

           Write column names in results.

       o   --comments, -c

           Whether to preserve comments in statements sent to the server. The
           default is --skip-comments (discard comments), enable with
           --comments (preserve comments). This option was added in MySQL

       o   --compress, -C

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

       o   --database=db_name, -D db_name

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

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

           Write a debugging log. A typical debug_options string is
           'd:t:o,file_name'. The default is 'd:t:o,/tmp/mysql.trace'.

       o   --debug-info, -T

           Print some debugging information when the program exits.

       o   --default-character-set=charset_name

           Use charset_name as the default character set for the client and

           A common issue that can occur when the operating system uses utf8
           or another multi-byte character set is that output from the mysql
           client is formatted incorrectly, due to the fact that the MySQL
           client uses the latin1 character set by default. You can usually
           fix such issues by using this option to force the client to use the
           system character set instead.

           See Section 9.2, "The Character Set Used for Data and Sorting", for
           more information.

       o   --delimiter=str

           Set the statement delimiter. The default is the semicolon character

       o   --disable-named-commands

           Disable named commands. Use the \* form only, or use named commands
           only at the beginning of a line ending with a semicolon (";").
           mysql starts with this option enabled by default. However, even
           with this option, long-format commands still work from the first
           line. See the section called "MYSQL COMMANDS".

       o   --execute=statement, -e statement

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

       o   --force, -f

           Continue even if an SQL error occurs.

       o   --host=host_name, -h host_name

           Connect to the MySQL server on the given host.

       o   --html, -H

           Produce HTML output.

       o   --ignore-spaces, -i

           Ignore spaces after function names. The effect of this is described
           in the discussion for the IGNORE_SPACE SQL mode (see Section 5.1.7,
           "Server SQL Modes").

       o   --line-numbers

           Write line numbers for errors. Disable this with

       o   --local-infile[={0|1}]

           Enable or disable LOCAL capability for LOAD DATA INFILE. With no
           value, the option enables LOCAL. The option 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.

       o   --named-commands, -G

           Enable named mysql commands. Long-format commands are allowed, not
           just short-format commands. For example, quit and \q both are
           recognized. Use --skip-named-commands to disable named commands.
           See the section called "MYSQL COMMANDS".

       o   --no-auto-rehash, -A

           Deprecated form of -skip-auto-rehash. Use --disable-auto-rehash
           instead. See the description for --auto-rehash.

       o   --no-beep, -b

           Do not beep when errors occur.

       o   --no-named-commands, -g

           Deprecated, use --disable-named-commands instead.

       o   --no-pager

           Deprecated form of --skip-pager. See the --pager option.

       o   --no-tee

           Do not copy output to a file.  the section called "MYSQL COMMANDS",
           discusses tee files further.

       o   --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.

       o   --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 and only in interactive mode.
           To disable paging, use --skip-pager.  the section called "MYSQL
           COMMANDS", discusses output paging further.

       o   --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

           Specifying a password on the command line should be considered
           insecure. See Section, "End-User Guidelines for Password

       o   --pipe, -W

           On Windows, connect to the server via a named pipe. This option
           applies only for connections to a local server, and only if the
           server supports named-pipe connections.

       o   --port=port_num, -P port_num

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

       o   --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 "MYSQL COMMANDS".

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

           The connection protocol to use for connecting to the server. It is
           useful when the other connection parameters normally would cause a
           protocol to be used other than the one you want. For details on the
           allowable values, see Section 4.2.2, "Connecting to the MySQL

       o   --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.

       o   --raw, -r

           For tabular output, the "boxing" around columns enables one column
           value to be distinguished from another. For nontabular output (such
           as is produced in batch mode or when the --batch or --silent option
           is given), special characters are escaped in the output so they can
           be identified easily. Newline, tab, NUL, and backslash are written
           as \n, \t, \0, and \\. The --raw option disables this character

           The following example demonstrates tabular versus nontabular output
           and the use of raw mode to disable escaping:

               % mysql
               mysql> SELECT CHAR(92);
               | CHAR(92) |
               | \        |
               % mysql -s
               mysql> SELECT CHAR(92);
               % mysql -s -r
               mysql> SELECT CHAR(92);

       o   --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

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

           Allow only those UPDATE and DELETE statements that specify which
           rows to modify by 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 "MYSQL TIPS", for more
           information about this option.

       o   --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

       o   --show-warnings

           Cause warnings to be shown after each statement if there are any.
           This option applies to interactive and batch mode. This option was
           added in MySQL 5.0.6.

       o   --sigint-ignore

           Ignore SIGINT signals (typically the result of typing Control-C).

       o   --silent, -s

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

           This option results in nontabular output format and escaping of
           special characters. Escaping may be disabled by using raw mode; see
           the description for the --raw option.

       o   --skip-column-names, -N

           Do not write column names in results. The short format, -N is
           deprecated, use the long format instead.

       o   --skip-line-numbers, -L

           Do not write line numbers for errors. Useful when you want to
           compare result files that include error messages. The short format,
           -L is deprecated, use the long format instead.

       o   --socket=path, -S path

           For connections to localhost, the Unix socket file to use, or, on
           Windows, the name of the named pipe to use.

       o   --ssl*

           Options that begin with --ssl specify whether to connect to the
           server via SSL and indicate where to find SSL keys and
           certificates. See Section, "SSL Command Options".

       o   --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.

       o   --tee=file_name

           Append a copy of output to the given file. This option works only
           in interactive mode.  the section called "MYSQL COMMANDS",
           discusses tee files further.

       o   --unbuffered, -n

           Flush the buffer after each query.

       o   --user=user_name, -u user_name

           The MySQL user name to use when connecting to the server.

       o   --verbose, -v

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

       o   --version, -V

           Display version information and exit.

       o   --vertical, -E

           Print query output rows vertically (one line per column value).
           Without this option, you can specify vertical output for individual
           statements by terminating them with \G.

       o   --wait, -w

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

       o   --xml, -X

           Produce XML output.

               Prior to MySQL 5.0.26, there was no differentiation in the
               output when using this option between columns containing the
               NULL value and columns containing the string literal 'NULL';
               both were represented as

               <field name="column_name">NULL</field>

           Beginning with MySQL 5.0.26, the output when --xml is used with
           mysql matches that of mysqldump --xml. See mysqldump(1) for

           Beginning with MySQL 5.0.40, the XML output also uses an XML
           namespace, as shown here:

               shell> mysql --xml -uroot -e "SHOW VARIABLES LIKE 'version%'"
               <?xml version="1.0"?>
               <resultset statement="SHOW VARIABLES LIKE 'version%'" xmlns:xsi="">
               <field name="Variable_name">version</field>
               <field name="Value">5.0.40-debug</field>
               <field name="Variable_name">version_comment</field>
               <field name="Value">Source distribution</field>
               <field name="Variable_name">version_compile_machine</field>
               <field name="Value">i686</field>
               <field name="Variable_name">version_compile_os</field>
               <field name="Value">suse-linux-gnu</field>

           (See Bug#25946[1].)

       You can also set the following variables by using --var_name=value. The
       --set-variable format is deprecated.

       o   connect_timeout

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

       o   max_allowed_packet

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

       o   max_join_size

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

       o   net_buffer_length

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

       o   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 --var_name=value. The
       --set-variable format is deprecated.

       On Unix, the mysql client writes a record of executed statements to a
       history file. By default, this 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.

       The .mysql_history should be protected with a restrictive access mode
       because sensitive information might be written to it, such as the text
       of SQL statements that contain passwords. See Section, "End-
       User Guidelines for Password Security".

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

       o   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.

       o   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 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 command.
           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
           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.
           For server side help, type 'help contents'

       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.

       o   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 the section
           called "MYSQL SERVER-SIDE HELP".

       o   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. This command was added in MySQL 5.0.19.

       o   clear, \c

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

       o   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

       o   delimiter str, \d str

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

           The delimiter can be specified as an unquoted or quoted argument.
           Quoting can be done with either single quote (') or douple quote
           (") characters. To include a quote within a quoted string, either
           quote the string with the other 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 delmiter 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.

           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 20.8.12, "C API Support
           for Multiple Statement Execution"), and for parsing the body of
           stored procedures and functions and triggers (see Section 18.1,
           "Defining Stored Programs").

       o   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.

       o   ego, \G

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

       o   exit, \q

           Exit mysql.

       o   go, \g

           Send the current statement to the server to be executed.

       o   nopager, \n

           Disable output paging. See the description for pager.

           The nopager command works only in Unix.

       o   notee, \t

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

       o   nowarning, \w

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

       o   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

           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.

       o   print, \p

           Print the current input statement without executing it.

       o   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>.

       o   quit, \q

           Exit mysql.

       o   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.)

       o   source file_name, \. file_name

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

       o   status, \s

           Provide status 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.

       o   system command, \! command

           Execute the given command using your default command interpreter.

           The system command works only in Unix.

       o   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

       o   use db_name, \u db_name

           Use db_name as the default database.

       o   warnings, \W

           Enable 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:

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

               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

       o   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

       o   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

               mysql> pager less -n -i -S -F -X

       o   You can specify very complex pager commands for handling query

               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 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

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

       |Option | Description                |
       |\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 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:

       o   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]> "

       o   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]>

       o   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:

               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. (The rules for escape sequences in option files
           are listed in Section, "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:

               prompt="\\r:\\m:\\s> "

       o   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> help search_string

       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. The proper operation of this command requires that
       the help tables in the mysql database be initialized with help topic
       information (see Section 5.1.8, "Server-Side Help").

       If there is no match for the search string, the search fails:

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

       Use help contents to see a list of the help categories:

           mysql> help 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
              Data Definition
              Data Manipulation
              Data Types
              Functions and Modifiers for Use with GROUP BY
              Geographic Features
              Language Structure
              Storage Engines
              Stored Routines
              Table Maintenance

       If the search string matches multiple items, mysql shows a list of
       matching topics:

           mysql> help logs
           Many help items for your request exist.
           To make a more specific request, please type 'help <item>',
           where <item> is one of the following topics:
              SHOW BINARY LOGS
              SHOW ENGINE
              SHOW LOGS

       Use a topic as the search string to see the help entry for that topic:

           mysql> help show binary logs
           Name: 'SHOW BINARY LOGS'
           Lists the binary log files on the server. This statement is used as
           part of the procedure described in [purge-binary-logs], that shows how
           to determine which logs can be purged.
           mysql> SHOW BINARY LOGS;
           | Log_name      | File_size |
           | binlog.000015 |    724935 |
           | binlog.000016 |    733481 |


       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

       If you place a USE db_name statement as the first statement in the
       file, it is unnecessary to specify the database name on the command

           shell> mysql < text_file

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

           mysql> source file_name
           mysql> \. file_name

       Sometimes you may want your script to display progress information to
       the user. For this you can insert statements like this:

           SELECT '<info_to_display>' AS ' ';

       The statement shown outputs <info_to_display>.

       You can also invoke mysql with the --verbose option, which causes each
       statement to be displayed before the result that it produces.

       As of MySQL 5.0.54, mysql ignores Unicode byte order mark (BOM)
       characters at the beginning of input files. Previously, it read them
       and sent them to the server, resulting in a syntax error. Presence of a
       BOM does not cause mysql to change its default character set. To do
       that, invoke mysql with an option such as --default-character-set=utf8.

       For more information about batch mode, see Section 3.5, "Using mysql in
       Batch Mode".


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

   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
             mail_to: "Thimble Smith" <>
                 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.
                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). 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

       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 5.1.4, "Session System Variables".

       The SET statement has the following effects:

       o   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;

       o   The server limits all large SELECT results to 1,000 rows unless the
           statement includes a LIMIT clause.

       o   The server aborts multiple-table SELECT statements that probably
           need to examine more than 1,000,000 row combinations.

       To specify limits different from 1,000 and 1,000,000, you can override
       the defaults by using the --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
       statement, it immediately and automatically tries to reconnect once to
       the server and send the statement 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-defined and session variables. Also, any
       current transaction rolls back. This behavior may be dangerous for you,
       as in the following example where the server was shut down and
       restarted between the first and second statements without you knowing

           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.

       For more information about auto-reconnect and its effect on state
       information when a reconnection occurs, see Section 20.8.11,
       "Controlling Automatic Reconnection Behavior".


       Copyright 2007-2008 MySQL AB, 2009 Sun Microsystems, Inc.

       This documentation is free software; you can redistribute it and/or
       modify it only under the terms of the GNU General Public License as
       published by the Free Software Foundation; version 2 of the License.

       This documentation is distributed in the hope that it will be useful,
       but WITHOUT ANY WARRANTY; without even the implied warranty of
       General Public License for more details.

       You should have received a copy of the GNU General Public License along
       with the program; if not, write to the Free Software Foundation, Inc.,
       51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see


        1. Bug#25946


       For more information, please refer to the MySQL Reference Manual, which
       may already be installed locally and which is also available online at


       Sun Microsystems, Inc. (

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