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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 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 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

       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.

       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 > output.tab

MYSQL OPTIONS
       mysql supports the following options:

         --help, -?

          Display a help message and exit.

         --auto-rehash

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

         --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 8.1, "The Character Set Used for
          Data and Sorting".

         --column-names

          Write column names in results.

         --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 primarily 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_name

          Use charset_name as the default character set. See Section 8.1, "The Character Set Used for Data
          and Sorting".

         --delimiter=str

          Set the statement delimiter. The default is the semicolon character (`;').

         --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-spaces, -i

          Ignore spaces after function names. The effect of this is described in the discussion for the
          IGNORE_SPACE SQL mode (see the section called "SQL MODES").

         --line-numbers

          Write line numbers for errors. Disable this with --skip-line-numbers.

         --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.

       MySQL Enterprise. For expert advice on the security implications of enabling LOCAL, subscribe to the
       MySQL Network Monitoring and Advisory Service. For more information see
       http://www.mysql.com/products/enterprise/advisors.html.

         --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".

         --no-auto-rehash, -A

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

         --no-beep, -b

          Do not beep when errors occur.

         --no-named-commands, -g

          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".

         --no-pager

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

         --no-tee

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

         --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. To disable paging, use
          --skip-pager.  the section called "MYSQL COMMANDS", discusses output paging further.

         --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.

          Specifying a password on the command line should be considered insecure. See Section 6.6, "Keeping
          Your Password Secure".

         --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 "MYSQL COMMANDS".

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

          The connection protocol to use.

         --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.

         --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.

         --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.

       MySQL Enterprise. For expert advice on database security, subscribe to the MySQL Network Monitoring
       and Advisory Service. For more information see
       http://www.mysql.com/products/enterprise/advisors.html

         --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.

         --sigint-ignore

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

         --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

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

         --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 6.7.3, "SSL Command Options".

         --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. in the section
          called "MYSQL COMMANDS", discusses tee files further.

         --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 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 mode.)

         --version, -V

          Display version information and exit.

         --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.

         --wait, -w

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

         --xml, -X

          Produce XML output.

          Note: 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 the section of the Manual which discusses the --xml option for mysqldump for details.

       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="http://www.w3.org/2001/XMLSchema-instance">
          <row>
          <field name="Variable_name">version</field>
          <field name="Value">5.0.40-debug</field>
          </row>
          <row>
          <field name="Variable_name">version_comment</field>
          <field name="Value">Source distribution</field>
          </row>
          <row>
          <field name="Variable_name">version_compile_machine</field>
          <field name="Value">i686</field>
          </row>
          <row>
          <field name="Variable_name">version_compile_os</field>
          <field name="Value">suse-linux-gnu</field>
          </row>
          </resultset>

       (See [1]Bug#25946.)


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

         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.  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 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'.
          charset   (\C) Switch to another charset. Might be needed for processing
                         binlog with multi-byte charsets.
          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.
          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.

       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".

       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 changed character set is used for reconnects. This
       command was added in MySQL 5.0.25.

       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.

       By using the --pager option, 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 this is not
       as convenient as pager for browsing output in some situations.

       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

         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.

       The default mysql> prompt can be reconfigured. The string for defining the prompt can contain the
       following special sequences:

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

       `\' 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 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 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>

MYSQL SERVER-SIDE HELP
          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 the section called "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
             Administration
             Data Definition
             Data Manipulation
             Data Types
             Functions
             Functions and Modifiers for Use with GROUP BY
             Geographic Features
             Language Structure
             Storage Engines
             Stored Routines
             Table Maintenance
             Transactions
             Triggers

       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
             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'
          Description:
          Syntax:
          SHOW BINARY LOGS
          SHOW MASTER LOGS
          Lists the binary log files on the server. This statement is used as
          part of the procedure described in [purge-master-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 |
          +---------------+-----------+

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

       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 line:

          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>.

       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). 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;

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

         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 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.

       For more information about auto-reconnect and its effect on state information when a reconnection
       occurs, see Section 2.13, "Controlling Automatic Reconnect Behavior".

COPYRIGHT
       Copyright 1997-2007 MySQL AB

       This documentation is NOT distributed under a GPL license. Use of this documentation is subject to
       the following terms: You may create a printed copy of this documentation solely for your own personal
       use. Conversion to other formats is allowed as long as the actual content is not altered or edited in
       any way. You shall not publish or distribute this documentation in any form or on any media, except
       if you distribute the documentation in a manner similar to how MySQL disseminates it (that is,
       electronically for download on a Web site with the software) or on a CD-ROM or similar medium,
       provided however that the documentation is disseminated together with the software on the same
       medium. Any other use, such as any dissemination of printed copies or use of this documentation, in
       whole or in part, in another publication, requires the prior written consent from an authorized
       representative of MySQL AB. MySQL AB reserves any and all rights to this documentation not expressly
       granted above.

       Please email <docs@mysql.com> for more information.

REFERENCES
       1. Bug#25946
          http://bugs.mysql.com/25946

SEE ALSO
       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 5.0                                        07/04/2007                                         MYSQL(1)

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