Imported freely distributable documentation from upstream MySQL 5.1.34 source tarball.

1 files changed, 1699 insertions, 0 deletions

diff --git a/man/mysql.1 b/man/mysql.1
new file mode 100644
index 00000000000..544ad973e46
--- /dev/null
+++ b/man/mysql.1
@@ -0,0 +1,1699 @@
+.\"     Title: \fBmysql\fR
+.\"    Author: 
+.\" Generator: DocBook XSL Stylesheets v1.70.1 <http://docbook.sf.net/>
+.\"      Date: 03/31/2009
+.\"    Manual: MySQL Database System
+.\"    Source: MySQL 5.1
+.\"
+.TH "\fBMYSQL\fR" "1" "03/31/2009" "MySQL 5.1" "MySQL Database System"
+.\" disable hyphenation
+.nh
+.\" disable justification (adjust text to left margin only)
+.ad l
+.SH "NAME"
+mysql \- the MySQL command\-line tool
+.SH "SYNOPSIS"
+.HP 24
+\fBmysql [\fR\fB\fIoptions\fR\fR\fB] \fR\fB\fIdb_name\fR\fR
+.SH "DESCRIPTION"
+.PP
+\fBmysql\fR
+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.
+.PP
+If you have problems due to insufficient memory for large result sets, use the
+\fB\-\-quick\fR
+option. This forces
+\fBmysql\fR
+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().
+.PP
+Using
+\fBmysql\fR
+is very easy. Invoke it from the prompt of your command interpreter as follows:
+.sp
+.RS 3n
+.nf
+shell> \fBmysql \fR\fB\fIdb_name\fR\fR
+.fi
+.RE
+.PP
+Or:
+.sp
+.RS 3n
+.nf
+shell> \fBmysql \-\-user=\fR\fB\fIuser_name\fR\fR\fB \-\-password=\fR\fB\fIyour_password\fR\fR\fB \fR\fB\fIdb_name\fR\fR
+.fi
+.RE
+.PP
+Then type an SQL statement, end it with
+\(lq;\(rq,
+\\g, or
+\\G
+and press Enter.
+.PP
+As of MySQL 5.1.10, typing Control\-C causes
+\fBmysql\fR
+to attempt to kill the current statement. If this cannot be done, or Control\-C is typed again before the statement is killed,
+\fBmysql\fR
+exits. Previously, Control\-C caused
+\fBmysql\fR
+to exit in all cases.
+.PP
+You can execute SQL statements in a script file (batch file) like this:
+.sp
+.RS 3n
+.nf
+shell> \fBmysql \fR\fB\fIdb_name\fR\fR\fB < \fR\fB\fIscript.sql\fR\fR\fB > \fR\fB\fIoutput.tab\fR\fR
+.fi
+.RE
+.SH "\fBMYSQL\fR OPTIONS"
+.PP
+\fBmysql\fR
+supports the following options:
+.TP 3n
+\(bu
+\fB\-\-help\fR,
+\fB\-?\fR
+.sp
+Display a help message and exit.
+.TP 3n
+\(bu
+\fB\-\-auto\-rehash\fR
+.sp
+Enable automatic rehashing. This option is on by default, which enables database, table, and column name completion. Use
+\fB\-\-disable\-auto\-rehash\fR
+to disable rehashing. That causes
+\fBmysql\fR
+to start faster, but you must issue the
+rehash
+command if you want to use name completion.
+.sp
+To complete a name, enter the first part and press Tab. If the name is unambiguous,
+\fBmysql\fR
+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.
+.TP 3n
+\(bu
+\fB\-\-batch\fR,
+\fB\-B\fR
+.sp
+Print results using tab as the column separator, with each row on a new line. With this option,
+\fBmysql\fR
+does not use the history file.
+.sp
+Batch mode results in non\-tabular output format and escaping of special characters. Escaping may be disabled by using raw mode; see the description for the
+\fB\-\-raw\fR
+option.
+.TP 3n
+\(bu
+\fB\-\-character\-sets\-dir=\fR\fB\fIpath\fR\fR
+.sp
+The directory where character sets are installed. See
+Section\ 9.2, \(lqThe Character Set Used for Data and Sorting\(rq.
+.TP 3n
+\(bu
+\fB\-\-column\-names\fR
+.sp
+Write column names in results.
+.TP 3n
+\(bu
+\fB\-\-column\-type\-info\fR,
+\fB\-m\fR
+.sp
+Display result set metadata. This option was added in MySQL 5.1.14. (Before that, use
+\fB\-\-debug\-info\fR.) The
+\fB\-m\fR
+short option was added in MySQL 5.1.21.
+.TP 3n
+\(bu
+\fB\-\-comments\fR,
+\fB\-c\fR
+.sp
+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 5.1.23.
+.TP 3n
+\(bu
+\fB\-\-compress\fR,
+\fB\-C\fR
+.sp
+Compress all information sent between the client and the server if both support compression.
+.TP 3n
+\(bu
+\fB\-\-database=\fR\fB\fIdb_name\fR\fR,
+\fB\-D \fR\fB\fIdb_name\fR\fR
+.sp
+The database to use. This is useful primarily in an option file.
+.TP 3n
+\(bu
+\fB\-\-debug[=\fR\fB\fIdebug_options\fR\fR\fB]\fR,
+\fB\-# [\fR\fB\fIdebug_options\fR\fR\fB]\fR
+.sp
+Write a debugging log. The
+\fIdebug_options\fR
+string often is
+\'d:t:o,\fIfile_name\fR'. The default is
+\'d:t:o,/tmp/mysql.trace'.
+.TP 3n
+\(bu
+\fB\-\-debug\-check\fR
+.sp
+Print some debugging information when the program exits. This option was added in MySQL 5.1.21.
+.TP 3n
+\(bu
+\fB\-\-debug\-info\fR,
+\fB\-T\fR
+.sp
+Before MySQL 5.1.14, this option prints debugging information and memory and CPU usage statistics when the program exits, and also causes display of result set metadata during execution. As of MySQL 5.1.14, use
+\fB\-\-column\-type\-info\fR
+to display result set metadata.
+.TP 3n
+\(bu
+\fB\-\-default\-character\-set=\fR\fB\fIcharset_name\fR\fR
+.sp
+Use
+\fIcharset_name\fR
+as the default character set. See
+Section\ 9.2, \(lqThe Character Set Used for Data and Sorting\(rq.
+.TP 3n
+\(bu
+\fB\-\-delimiter=\fR\fB\fIstr\fR\fR
+.sp
+Set the statement delimiter. The default is the semicolon character (\(lq;\(rq).
+.TP 3n
+\(bu
+\fB\-\-disable\-named\-commands\fR
+.sp
+Disable named commands. Use the
+\\*
+form only, or use named commands only at the beginning of a line ending with a semicolon (\(lq;\(rq).
+\fBmysql\fR
+starts with this option
+\fIenabled\fR
+by default. However, even with this option, long\-format commands still work from the first line. See
+the section called \(lq\fBMYSQL\fR COMMANDS\(rq.
+.TP 3n
+\(bu
+\fB\-\-execute=\fR\fB\fIstatement\fR\fR,
+\fB\-e \fR\fB\fIstatement\fR\fR
+.sp
+Execute the statement and quit. The default output format is like that produced with
+\fB\-\-batch\fR. See
+Section\ 4.2.3.1, \(lqUsing Options on the Command Line\(rq, for some examples.
+.TP 3n
+\(bu
+\fB\-\-force\fR,
+\fB\-f\fR
+.sp
+Continue even if an SQL error occurs.
+.TP 3n
+\(bu
+\fB\-\-host=\fR\fB\fIhost_name\fR\fR,
+\fB\-h \fR\fB\fIhost_name\fR\fR
+.sp
+Connect to the MySQL server on the given host.
+.TP 3n
+\(bu
+\fB\-\-html\fR,
+\fB\-H\fR
+.sp
+Produce HTML output.
+.TP 3n
+\(bu
+\fB\-\-ignore\-spaces\fR,
+\fB\-i\fR
+.sp
+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, \(lqServer SQL Modes\(rq).
+.TP 3n
+\(bu
+\fB\-\-line\-numbers\fR
+.sp
+Write line numbers for errors. Disable this with
+\fB\-\-skip\-line\-numbers\fR.
+.TP 3n
+\(bu
+\fB\-\-local\-infile[={0|1}]\fR
+.sp
+Enable or disable
+LOCAL
+capability for
+LOAD DATA INFILE. With no value, the option enables
+LOCAL. The option may be given as
+\fB\-\-local\-infile=0\fR
+or
+\fB\-\-local\-infile=1\fR
+to explicitly disable or enable
+LOCAL. Enabling
+LOCAL
+has no effect if the server does not also support it.
+.TP 3n
+\(bu
+\fB\-\-named\-commands\fR,
+\fB\-G\fR
+.sp
+Enable named
+\fBmysql\fR
+commands. Long\-format commands are allowed, not just short\-format commands. For example,
+quit
+and
+\\q
+both are recognized. Use
+\fB\-\-skip\-named\-commands\fR
+to disable named commands. See
+the section called \(lq\fBMYSQL\fR COMMANDS\(rq.
+.TP 3n
+\(bu
+\fB\-\-no\-auto\-rehash\fR,
+\fB\-A\fR
+.sp
+Deprecated form of
+\fB\-skip\-auto\-rehash\fR. Use
+\fB\-\-disable\-auto\-rehash\fR
+instead. See the description for
+\fB\-\-auto\-rehash\fR.
+.TP 3n
+\(bu
+\fB\-\-no\-beep\fR,
+\fB\-b\fR
+.sp
+Do not beep when errors occur.
+.TP 3n
+\(bu
+\fB\-\-no\-named\-commands\fR,
+\fB\-g\fR
+.sp
+Deprecated, use
+\fB\-\-disable\-named\-commands\fR
+instead.
+.TP 3n
+\(bu
+\fB\-\-no\-pager\fR
+.sp
+Deprecated form of
+\fB\-\-skip\-pager\fR. See the
+\fB\-\-pager\fR
+option.
+.TP 3n
+\(bu
+\fB\-\-no\-tee\fR
+.sp
+Do not copy output to a file.
+the section called \(lq\fBMYSQL\fR COMMANDS\(rq, discusses tee files further.
+.TP 3n
+\(bu
+\fB\-\-one\-database\fR,
+\fB\-o\fR
+.sp
+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.
+.TP 3n
+\(bu
+\fB\-\-pager[=\fR\fB\fIcommand\fR\fR\fB]\fR
+.sp
+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
+\fBless\fR,
+\fBmore\fR,
+\fBcat [> filename]\fR, and so forth. This option works only on Unix. It does not work in batch mode. To disable paging, use
+\fB\-\-skip\-pager\fR.
+the section called \(lq\fBMYSQL\fR COMMANDS\(rq, discusses output paging further.
+.TP 3n
+\(bu
+\fB\-\-password[=\fR\fB\fIpassword\fR\fR\fB]\fR,
+\fB\-p[\fR\fB\fIpassword\fR\fR\fB]\fR
+.sp
+The password to use when connecting to the server. If you use the short option form (\fB\-p\fR), you
+\fIcannot\fR
+have a space between the option and the password. If you omit the
+\fIpassword\fR
+value following the
+\fB\-\-password\fR
+or
+\fB\-p\fR
+option on the command line, you are prompted for one.
+.sp
+Specifying a password on the command line should be considered insecure. See
+Section\ 5.5.6.2, \(lqEnd\-User Guidelines for Password Security\(rq.
+.TP 3n
+\(bu
+\fB\-\-pipe\fR,
+\fB\-W\fR
+.sp
+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.
+.TP 3n
+\(bu
+\fB\-\-port=\fR\fB\fIport_num\fR\fR,
+\fB\-P \fR\fB\fIport_num\fR\fR
+.sp
+The TCP/IP port number to use for the connection.
+.TP 3n
+\(bu
+\fB\-\-prompt=\fR\fB\fIformat_str\fR\fR
+.sp
+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 \(lq\fBMYSQL\fR COMMANDS\(rq.
+.TP 3n
+\(bu
+\fB\-\-protocol={TCP|SOCKET|PIPE|MEMORY}\fR
+.sp
+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, \(lqConnecting to the MySQL Server\(rq.
+.TP 3n
+\(bu
+\fB\-\-quick\fR,
+\fB\-q\fR
+.sp
+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,
+\fBmysql\fR
+does not use the history file.
+.TP 3n
+\(bu
+\fB\-\-raw\fR,
+\fB\-r\fR
+.sp
+For tabular output, the
+\(lqboxing\(rq
+around columns enables one column value to be distinguished from another. For non\-tabular output (such as is produced in batch mode or when the
+\fB\-\-batch\fR
+or
+\fB\-\-silent\fR
+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
+\fB\-\-raw\fR
+option disables this character escaping.
+.sp
+The following example demonstrates tabular versus non\-tabular output and the use of raw mode to disable escaping:
+.sp
+.RS 3n
+.nf
+% \fBmysql\fR
+mysql> SELECT CHAR(92);
++\-\-\-\-\-\-\-\-\-\-+
+| CHAR(92) |
++\-\-\-\-\-\-\-\-\-\-+
+| \\        | 
++\-\-\-\-\-\-\-\-\-\-+
+% \fBmysql \-s\fR
+mysql> SELECT CHAR(92);
+CHAR(92)
+\\\\
+% \fBmysql \-s \-r\fR
+mysql> SELECT CHAR(92);
+CHAR(92)
+\\
+.fi
+.RE
+.TP 3n
+\(bu
+\fB\-\-reconnect\fR
+.sp
+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
+\fB\-\-skip\-reconnect\fR.
+.TP 3n
+\(bu
+\fB\-\-safe\-updates\fR,
+\fB\-\-i\-am\-a\-dummy\fR,
+\fB\-U\fR
+.sp
+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
+\fB\-\-safe\-updates\fR
+on the command line. See
+the section called \(lq\fBMYSQL\fR TIPS\(rq, for more information about this option.
+.TP 3n
+\(bu
+\fB\-\-secure\-auth\fR
+.sp
+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.
+.TP 3n
+\(bu
+\fB\-\-show\-warnings\fR
+.sp
+Cause warnings to be shown after each statement if there are any. This option applies to interactive and batch mode.
+.TP 3n
+\(bu
+\fB\-\-sigint\-ignore\fR
+.sp
+Ignore
+SIGINT
+signals (typically the result of typing Control\-C).
+.TP 3n
+\(bu
+\fB\-\-silent\fR,
+\fB\-s\fR
+.sp
+Silent mode. Produce less output. This option can be given multiple times to produce less and less output.
+.sp
+This option results in non\-tabular output format and escaping of special characters. Escaping may be disabled by using raw mode; see the description for the
+\fB\-\-raw\fR
+option.
+.TP 3n
+\(bu
+\fB\-\-skip\-column\-names\fR,
+\fB\-N\fR
+.sp
+Do not write column names in results. The short format,
+\fB\-N\fR
+is deprecated, use the long format instead.
+.TP 3n
+\(bu
+\fB\-\-skip\-line\-numbers\fR,
+\fB\-L\fR
+.sp
+Do not write line numbers for errors. Useful when you want to compare result files that include error messages. The short format,
+\fB\-L\fR
+is deprecated, use the long format instead.
+.TP 3n
+\(bu
+\fB\-\-socket=\fR\fB\fIpath\fR\fR,
+\fB\-S \fR\fB\fIpath\fR\fR
+.sp
+For connections to
+localhost, the Unix socket file to use, or, on Windows, the name of the named pipe to use.
+.TP 3n
+\(bu
+\fB\-\-ssl*\fR
+.sp
+Options that begin with
+\fB\-\-ssl\fR
+specify whether to connect to the server via SSL and indicate where to find SSL keys and certificates. See
+Section\ 5.5.7.3, \(lqSSL Command Options\(rq.
+.TP 3n
+\(bu
+\fB\-\-table\fR,
+\fB\-t\fR
+.sp
+Display output in table format. This is the default for interactive use, but can be used to produce table output in batch mode.
+.TP 3n
+\(bu
+\fB\-\-tee=\fR\fB\fIfile_name\fR\fR
+.sp
+Append a copy of output to the given file. This option does not work in batch mode.
+the section called \(lq\fBMYSQL\fR COMMANDS\(rq, discusses tee files further.
+.TP 3n
+\(bu
+\fB\-\-unbuffered\fR,
+\fB\-n\fR
+.sp
+Flush the buffer after each query.
+.TP 3n
+\(bu
+\fB\-\-user=\fR\fB\fIuser_name\fR\fR,
+\fB\-u \fR\fB\fIuser_name\fR\fR
+.sp
+The MySQL user name to use when connecting to the server.
+.TP 3n
+\(bu
+\fB\-\-verbose\fR,
+\fB\-v\fR
+.sp
+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,
+\fB\-v \-v \-v\fR
+produces table output format even in batch mode.)
+.TP 3n
+\(bu
+\fB\-\-version\fR,
+\fB\-V\fR
+.sp
+Display version information and exit.
+.TP 3n
+\(bu
+\fB\-\-vertical\fR,
+\fB\-E\fR
+.sp
+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.
+.TP 3n
+\(bu
+\fB\-\-wait\fR,
+\fB\-w\fR
+.sp
+If the connection cannot be established, wait and retry instead of aborting.
+.TP 3n
+\(bu
+\fB\-\-xml\fR,
+\fB\-X\fR
+.sp
+Produce XML output.
+.sp
+.it 1 an-trap
+.nr an-no-space-flag 1
+.nr an-break-flag 1
+.br
+\fBNote\fR
+Prior to MySQL 5.1.12, 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
+.sp
+.RS 3n
+.nf
+<field name="\fIcolumn_name\fR">NULL</field>
+.fi
+.RE
+Beginning with MySQL 5.1.12, the output when
+\fB\-\-xml\fR
+is used with
+\fBmysql\fR
+matches that of
+\fBmysqldump \fR\fB\fB\-\-xml\fR\fR. See
+\fBmysqldump\fR(1)
+for details.
+.sp
+Beginning with MySQL 5.1.18, the XML output also uses an XML namespace, as shown here:
+.sp
+.RS 3n
+.nf
+shell> \fBmysql \-\-xml \-uroot \-e "SHOW VARIABLES LIKE 'version%'"\fR
+<?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>
+.fi
+.RE
+.sp
+(See
+[1]\&\fIBug#25946\fR.)
+.sp
+.RE
+.PP
+You can also set the following variables by using
+\fB\-\-\fR\fB\fIvar_name\fR\fR\fB=\fR\fB\fIvalue\fR\fR. The
+\fB\-\-set\-variable\fR
+format is deprecated.
+.TP 3n
+\(bu
+connect_timeout
+.sp
+The number of seconds before connection timeout. (Default value is
+0.)
+.TP 3n
+\(bu
+max_allowed_packet
+.sp
+The maximum packet length to send to or receive from the server. (Default value is 16MB.)
+.TP 3n
+\(bu
+max_join_size
+.sp
+The automatic limit for rows in a join when using
+\fB\-\-safe\-updates\fR. (Default value is 1,000,000.)
+.TP 3n
+\(bu
+net_buffer_length
+.sp
+The buffer size for TCP/IP and socket communication. (Default value is 16KB.)
+.TP 3n
+\(bu
+select_limit
+.sp
+The automatic limit for
+SELECT
+statements when using
+\fB\-\-safe\-updates\fR. (Default value is 1,000.)
+.sp
+.RE
+.PP
+On Unix, the
+\fBmysql\fR
+client writes a record of executed statements to a history file. By default, this file is named
+\fI.mysql_history\fR
+and is created in your home directory. To specify a different file, set the value of the
+MYSQL_HISTFILE
+environment variable.
+.PP
+The
+\fI.mysql_history\fR
+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\ 5.5.6.2, \(lqEnd\-User Guidelines for Password Security\(rq.
+.PP
+If you do not want to maintain a history file, first remove
+\fI.mysql_history\fR
+if it exists, and then use either of the following techniques:
+.TP 3n
+\(bu
+Set the
+MYSQL_HISTFILE
+variable to
+\fI/dev/null\fR. To cause this setting to take effect each time you log in, put the setting in one of your shell's startup files.
+.TP 3n
+\(bu
+Create
+\fI.mysql_history\fR
+as a symbolic link to
+\fI/dev/null\fR:
+.sp
+.RS 3n
+.nf
+shell> \fBln \-s /dev/null $HOME/.mysql_history\fR
+.fi
+.RE
+You need do this only once.
+.SH "\fBMYSQL\fR COMMANDS"
+.PP
+\fBmysql\fR
+sends each SQL statement that you issue to the server to be executed. There is also a set of commands that
+\fBmysql\fR
+itself interprets. For a list of these commands, type
+help
+or
+\\h
+at the
+mysql>
+prompt:
+.sp
+.RS 3n
+.nf
+mysql> \fBhelp\fR
+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
+               outfile.
+use       (\\u) Use another database. Takes database name as argument.
+charset   (\\C) Switch to another charset. Might be needed for processing
+               binlog with multi\-byte charsets.
+warnings  (\\W) Show warnings after every statement.
+nowarning (\\w) Don't show warnings after every statement.
+For server side help, type 'help contents'
+.fi
+.RE
+.PP
+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.
+.PP
+The use of short\-form commands within multi\-line
+/* ... */
+comments is not supported.
+.TP 3n
+\(bu
+\fBhelp [\fR\fB\fIarg\fR\fR\fB]\fR,
+\fB\\h [\fR\fB\fIarg\fR\fR\fB]\fR,
+\fB\\? [\fR\fB\fIarg\fR\fR\fB]\fR,
+\fB? [\fR\fB\fIarg\fR\fR\fB]\fR
+.sp
+Displays a help message listing the available
+\fBmysql\fR
+commands.
+.sp
+If you provide an argument to the
+help
+command,
+\fBmysql\fR
+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 \(lq\fBMYSQL\fR SERVER\-SIDE HELP\(rq.
+.TP 3n
+\(bu
+\fBcharset \fR\fB\fIcharset_name\fR\fR,
+\fB\\C \fR\fB\fIcharset_name\fR\fR
+.sp
+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
+\fBmysql\fR
+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 5.1.7.
+.TP 3n
+\(bu
+\fBclear\fR,
+\fB\\c\fR
+.sp
+Clears the current input. Use this if you change your mind about executing the statement that you are entering.
+.TP 3n
+\(bu
+\fBconnect [\fR\fB\fIdb_name\fR\fR\fB \fR\fB\fIhost_name\fR\fR\fB]]\fR,
+\fB\\r [\fR\fB\fIdb_name\fR\fR\fB \fR\fB\fIhost_name\fR\fR\fB]]\fR
+.sp
+Reconnects to the server. The optional database name and host name arguments may be given to specify the default database or the host where the server is running. If omitted, the current values are used.
+.TP 3n
+\(bu
+\fBdelimiter \fR\fB\fIstr\fR\fR,
+\fB\\d \fR\fB\fIstr\fR\fR
+.sp
+The
+delimiter
+command changes the string that
+\fBmysql\fR
+interprets as the separator between SQL statements. The default is the semicolon character (\(lq;\(rq).
+.sp
+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 (\(lq\\\(rq) 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.
+.sp
+When the delimiter recognized by
+\fBmysql\fR
+is set to something other than the default of
+\(lq;\(rq, instances of that character are sent to the server without interpretation. However, the server itself still interprets
+\(lq;\(rq
+as a statement delimiter and processes statements accordingly. This behavior on the server side comes into play for multiple\-statement execution (see
+Section\ 21.10.12, \(lqC API Support for Multiple Statement Execution\(rq), and for parsing the body of stored procedures and functions, triggers, and events (see
+Section\ 19.1, \(lqDefining Stored Programs\(rq).
+.TP 3n
+\(bu
+\fBedit\fR,
+\fB\\e\fR
+.sp
+Edits the current input statement.
+\fBmysql\fR
+checks the values of the
+EDITOR
+and
+VISUAL
+environment variables to determine which editor to use. The default editor is
+\fBvi\fR
+if neither variable is set.
+.sp
+The
+\fBedit\fR
+command works only in Unix.
+.TP 3n
+\(bu
+\fBego\fR,
+\fB\\G\fR
+.sp
+Sends the current statement to the server to be executed and displays the result using vertical format.
+.TP 3n
+\(bu
+\fBexit\fR,
+\fB\\q\fR
+.sp
+Exits
+\fBmysql\fR.
+.TP 3n
+\(bu
+\fBgo\fR,
+\fB\\g\fR
+.sp
+Sends the current statement to the server to be executed.
+.TP 3n
+\(bu
+\fBnopager\fR,
+\fB\\n\fR
+.sp
+Disables output paging. See the description for
+\fBpager\fR.
+.sp
+The
+\fBnopager\fR
+command works only in Unix.
+.TP 3n
+\(bu
+\fBnotee\fR,
+\fB\\t\fR
+.sp
+Disables output copying to the tee file. See the description for
+\fBtee\fR.
+.TP 3n
+\(bu
+\fBnowarning\fR,
+\fB\\w\fR
+.sp
+Enables display of warnings after each statement.
+.TP 3n
+\(bu
+\fBpager [\fR\fB\fIcommand\fR\fR\fB]\fR,
+\fB\\P [\fR\fB\fIcommand\fR\fR\fB]\fR
+.sp
+By using the
+\fB\-\-pager\fR
+option when you invoke
+\fBmysql\fR, it is possible to browse or search query results in interactive mode with Unix programs such as
+\fBless\fR,
+\fBmore\fR, or any other similar program. If you specify no value for the option,
+\fBmysql\fR
+checks the value of the
+PAGER
+environment variable and sets the pager to that.
+.sp
+Output paging can be enabled interactively with the
+\fBpager\fR
+command and disabled with
+\fBnopager\fR. 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.
+.sp
+Output paging works only in Unix because it uses the
+popen()
+function, which does not exist on Windows. For Windows, the
+\fBtee\fR
+option can be used instead to save query output, although it is not as convenient as
+\fBpager\fR
+for browsing output in some situations.
+.TP 3n
+\(bu
+\fBprint\fR,
+\fB\\p\fR
+.sp
+Prints the current input statement without executing it.
+.TP 3n
+\(bu
+\fBprompt [\fR\fB\fIstr\fR\fR\fB]\fR,
+\fB\\R [\fR\fB\fIstr\fR\fR\fB]\fR
+.sp
+Reconfigures the
+\fBmysql\fR
+prompt to the given string. The special character sequences that can be used in the prompt are described later in this section.
+.sp
+If you specify the
+prompt
+command with no argument,
+\fBmysql\fR
+resets the prompt to the default of
+mysql>.
+.TP 3n
+\(bu
+\fBquit\fR,
+\fB\\q\fR
+.sp
+Exits
+\fBmysql\fR.
+.TP 3n
+\(bu
+\fBrehash\fR,
+\fB\\#\fR
+.sp
+Rebuilds the completion hash that enables database, table, and column name completion while you are entering statements. (See the description for the
+\fB\-\-auto\-rehash\fR
+option.)
+.TP 3n
+\(bu
+\fBsource \fR\fB\fIfile_name\fR\fR,
+\fB\\. \fR\fB\fIfile_name\fR\fR
+.sp
+Reads the named file and executes the statements contained therein. On Windows, you can specify path name separators as
+/
+or
+\\\\.
+.TP 3n
+\(bu
+\fBstatus\fR,
+\fB\\s\fR
+.sp
+The
+status
+command provides some information about the connection and the server you are using. If you are running in
+\fB\-\-safe\-updates\fR
+mode,
+status
+also prints the values for the
+\fBmysql\fR
+variables that affect your queries.
+.TP 3n
+\(bu
+\fBsystem \fR\fB\fIcommand\fR\fR,
+\fB\\! \fR\fB\fIcommand\fR\fR
+.sp
+Executes the given command using your default command interpreter.
+.sp
+The
+\fBsystem\fR
+command works only in Unix.
+.TP 3n
+\(bu
+\fBtee [\fR\fB\fIfile_name\fR\fR\fB]\fR,
+\fB\\T [\fR\fB\fIfile_name\fR\fR\fB]\fR
+.sp
+By using the
+\fB\-\-tee\fR
+option when you invoke
+\fBmysql\fR, 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.
+\fBmysql\fR
+flushes results to the file after each statement, just before it prints its next prompt.
+.sp
+You can enable this feature interactively with the
+\fBtee\fR
+command. Without a parameter, the previous file is used. The
+\fBtee\fR
+file can be disabled with the
+\fBnotee\fR
+command. Executing
+\fBtee\fR
+again re\-enables logging.
+.TP 3n
+\(bu
+\fBuse \fR\fB\fIdb_name\fR\fR,
+\fB\\u \fR\fB\fIdb_name\fR\fR
+.sp
+Uses
+\fIdb_name\fR
+as the default database.
+.TP 3n
+\(bu
+\fBwarnings\fR,
+\fB\\W\fR
+.sp
+Enables display of warnings after each statement (if there are any).
+.sp
+.RE
+.PP
+Here are a few tips about the
+\fBpager\fR
+command:
+.TP 3n
+\(bu
+You can use it to write to a file and the results go only to the file:
+.sp
+.RS 3n
+.nf
+mysql> \fBpager cat > /tmp/log.txt\fR
+.fi
+.RE
+You can also pass any options for the program that you want to use as your pager:
+.sp
+.RS 3n
+.nf
+mysql> \fBpager less \-n \-i \-S\fR
+.fi
+.RE
+.TP 3n
+\(bu
+In the preceding example, note the
+\fB\-S\fR
+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
+\fB\-S\fR
+option to
+\fBless\fR
+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
+\fB\-S\fR
+interactively within
+\fBless\fR
+to switch the horizontal\-browse mode on and off. For more information, read the
+\fBless\fR
+manual page:
+.sp
+.RS 3n
+.nf
+shell> \fBman less\fR
+.fi
+.RE
+.TP 3n
+\(bu
+The
+\fB\-F\fR
+and
+\fB\-X\fR
+options may be used with
+\fBless\fR
+to cause it to exit if output fits on one screen, which is convenient when no scrolling is necessary:
+.sp
+.RS 3n
+.nf
+mysql> \fBpager less \-n \-i \-S \-F \-X\fR
+.fi
+.RE
+.TP 3n
+\(bu
+You can specify very complex pager commands for handling query output:
+.sp
+.RS 3n
+.nf
+mysql> \fBpager cat | tee /dr1/tmp/res.txt \\\fR
+          \fB| tee /dr2/tmp/res2.txt | less \-n \-i \-S\fR
+.fi
+.RE
+In this example, the command would send query results to two files in two different directories on two different file systems mounted on
+\fI/dr1\fR
+and
+\fI/dr2\fR, yet still display the results onscreen via
+\fBless\fR.
+.sp
+.RE
+.PP
+You can also combine the
+\fBtee\fR
+and
+\fBpager\fR
+functions. Have a
+\fBtee\fR
+file enabled and
+\fBpager\fR
+set to
+\fBless\fR, and you are able to browse the results using the
+\fBless\fR
+program and still have everything appended into a file the same time. The difference between the Unix
+\fBtee\fR
+used with the
+\fBpager\fR
+command and the
+\fBmysql\fR
+built\-in
+\fBtee\fR
+command is that the built\-in
+\fBtee\fR
+works even if you do not have the Unix
+\fBtee\fR
+available. The built\-in
+\fBtee\fR
+also logs everything that is printed on the screen, whereas the Unix
+\fBtee\fR
+used with
+\fBpager\fR
+does not log quite that much. Additionally,
+\fBtee\fR
+file logging can be turned on and off interactively from within
+\fBmysql\fR. This is useful when you want to log some queries to a file, but not others.
+.PP
+The
+\fBprompt\fR
+command reconfigures the default
+mysql>
+prompt. The string for defining the prompt can contain the following special sequences.
+.TS
+allbox tab(:);
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l
+l l.
+T{
+\fBOption\fR
+T}:T{
+\fBDescription\fR
+T}
+T{
+\\o
+T}:T{
+The current month in numeric format
+T}
+T{
+\\P
+T}:T{
+am/pm
+T}
+T{
+\\p
+T}:T{
+The current TCP/IP port or socket file
+T}
+T{
+\\R
+T}:T{
+The current time, in 24\-hour military time (0\-23)
+T}
+T{
+\\r
+T}:T{
+The current time, standard 12\-hour time (1\-12)
+T}
+T{
+\\S
+T}:T{
+Semicolon
+T}
+T{
+\\s
+T}:T{
+Seconds of the current time
+T}
+T{
+\\t
+T}:T{
+A tab character
+T}
+T{
+\\U
+T}:T{
+Your full
+                \fIuser_name\fR@\fIhost_name\fR
+                account name
+T}
+T{
+\\u
+T}:T{
+Your user name
+T}
+T{
+\\c
+T}:T{
+A counter that increments for each statement you issue
+T}
+T{
+\\v
+T}:T{
+The server version
+T}
+T{
+\\w
+T}:T{
+The current day of the week in three\-letter format (Mon, Tue, \&...)
+T}
+T{
+\\Y
+T}:T{
+The current year, four digits
+T}
+T{
+\\y
+T}:T{
+The current year, two digits
+T}
+T{
+\\_
+T}:T{
+A space
+T}
+T{
+\\\ 
+T}:T{
+A space (a space follows the backslash)
+T}
+T{
+\\'
+T}:T{
+Single quote
+T}
+T{
+\\"
+T}:T{
+Double quote
+T}
+T{
+\\\\
+T}:T{
+A literal \(lq\\\(rq backslash character
+T}
+T{
+\\\fIx\fR
+T}:T{
+\fIx\fR, for any
+                \(lq\fIx\fR\(rq not listed
+                above
+T}
+T{
+\\D
+T}:T{
+The full current date
+T}
+T{
+\\d
+T}:T{
+The default database
+T}
+T{
+\\h
+T}:T{
+The server host
+T}
+T{
+\\l
+T}:T{
+The current delimiter (new in 5.1.12)
+T}
+T{
+\\m
+T}:T{
+Minutes of the current time
+T}
+T{
+\\n
+T}:T{
+A newline character
+T}
+T{
+\\O
+T}:T{
+The current month in three\-letter format (Jan, Feb, \&...)
+T}
+.TE
+.sp
+.PP
+You can set the prompt in several ways:
+.TP 3n
+\(bu
+\fIUse an environment variable.\fR
+You can set the
+MYSQL_PS1
+environment variable to a prompt string. For example:
+.sp
+.RS 3n
+.nf
+shell> \fBexport MYSQL_PS1="(\\u@\\h) [\\d]> "\fR
+.fi
+.RE
+.TP 3n
+\(bu
+\fIUse a command\-line option.\fR
+You can set the
+\fB\-\-prompt\fR
+option on the command line to
+\fBmysql\fR. For example:
+.sp
+.RS 3n
+.nf
+shell> \fBmysql \-\-prompt="(\\u@\\h) [\\d]> "\fR
+(user@host) [database]>
+.fi
+.RE
+.TP 3n
+\(bu
+\fIUse an option file.\fR
+You can set the
+prompt
+option in the
+[mysql]
+group of any MySQL option file, such as
+\fI/etc/my.cnf\fR
+or the
+\fI.my.cnf\fR
+file in your home directory. For example:
+.sp
+.RS 3n
+.nf
+[mysql]
+prompt=(\\\\u@\\\\h) [\\\\d]>\\\\_
+.fi
+.RE
+In this example, note that the backslashes are doubled. If you set the prompt using the
+prompt
+option in an option file, it is advisable to double the backslashes when using the special prompt options. There is some overlap in the set of allowable prompt options and the set of special escape sequences that are recognized in option files. (These sequences are listed in
+Section\ 4.2.3.2, \(lqUsing Option Files\(rq.) 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:
+.sp
+.RS 3n
+.nf
+[mysql]
+prompt="\\\\r:\\\\m:\\\\s> "
+.fi
+.RE
+.TP 3n
+\(bu
+\fISet the prompt interactively.\fR
+You can change your prompt interactively by using the
+prompt
+(or
+\\R) command. For example:
+.sp
+.RS 3n
+.nf
+mysql> \fBprompt (\\u@\\h) [\\d]>\\_\fR
+PROMPT set to '(\\u@\\h) [\\d]>\\_'
+(\fIuser\fR@\fIhost\fR) [\fIdatabase\fR]>
+(\fIuser\fR@\fIhost\fR) [\fIdatabase\fR]> prompt
+Returning to default PROMPT of mysql>
+mysql>
+.fi
+.RE
+.SH "\fBMYSQL\fR SERVER\-SIDE HELP"
+.sp
+.RS 3n
+.nf
+mysql> \fBhelp \fR\fB\fIsearch_string\fR\fR
+.fi
+.RE
+.PP
+If you provide an argument to the
+help
+command,
+\fBmysql\fR
+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, \(lqServer\-Side Help\(rq).
+.PP
+If there is no match for the search string, the search fails:
+.sp
+.RS 3n
+.nf
+mysql> \fBhelp me\fR
+Nothing found
+Please try to run 'help contents' for a list of all accessible topics
+.fi
+.RE
+.PP
+Use
+\fBhelp contents\fR
+to see a list of the help categories:
+.sp
+.RS 3n
+.nf
+mysql> \fBhelp contents\fR
+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
+   Plugins
+   Storage Engines
+   Stored Routines
+   Table Maintenance
+   Transactions
+   Triggers
+.fi
+.RE
+.PP
+If the search string matches multiple items,
+\fBmysql\fR
+shows a list of matching topics:
+.sp
+.RS 3n
+.nf
+mysql> \fBhelp logs\fR
+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
+.fi
+.RE
+.PP
+Use a topic as the search string to see the help entry for that topic:
+.sp
+.RS 3n
+.nf
+mysql> \fBhelp show binary logs\fR
+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\-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 |
++\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-+\-\-\-\-\-\-\-\-\-\-\-+
+.fi
+.RE
+.SH "EXECUTING SQL STATEMENTS FROM A TEXT FILE"
+.PP
+The
+\fBmysql\fR
+client typically is used interactively, like this:
+.sp
+.RS 3n
+.nf
+shell> \fBmysql \fR\fB\fIdb_name\fR\fR
+.fi
+.RE
+.PP
+However, it is also possible to put your SQL statements in a file and then tell
+\fBmysql\fR
+to read its input from that file. To do so, create a text file
+\fItext_file\fR
+that contains the statements you wish to execute. Then invoke
+\fBmysql\fR
+as shown here:
+.sp
+.RS 3n
+.nf
+shell> \fBmysql \fR\fB\fIdb_name\fR\fR\fB < \fR\fB\fItext_file\fR\fR
+.fi
+.RE
+.PP
+If you place a
+USE \fIdb_name\fR
+statement as the first statement in the file, it is unnecessary to specify the database name on the command line:
+.sp
+.RS 3n
+.nf
+shell> \fBmysql < text_file\fR
+.fi
+.RE
+.PP
+If you are already running
+\fBmysql\fR, you can execute an SQL script file using the
+source
+command or
+\\.
+command:
+.sp
+.RS 3n
+.nf
+mysql> \fBsource \fR\fB\fIfile_name\fR\fR
+mysql> \fB\\. \fR\fB\fIfile_name\fR\fR
+.fi
+.RE
+.PP
+Sometimes you may want your script to display progress information to the user. For this you can insert statements like this:
+.sp
+.RS 3n
+.nf
+SELECT '<info_to_display>' AS ' ';
+.fi
+.RE
+.PP
+The statement shown outputs
+<info_to_display>.
+.PP
+As of MySQL 5.1.23,
+\fBmysql\fR
+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
+\fBmysql\fR
+to change its default character set. To do that, invoke
+\fBmysql\fR
+with an option such as
+\fB\-\-default\-character\-set=utf8\fR.
+.PP
+For more information about batch mode, see
+Section\ 3.5, \(lqUsing \fBmysql\fR in Batch Mode\(rq.
+.SH "\fBMYSQL\fR TIPS"
+.PP
+This section describes some techniques that can help you use
+\fBmysql\fR
+more effectively.
+.SS "Displaying Query Results Vertically"
+.PP
+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:
+.sp
+.RS 3n
+.nf
+mysql> \fBSELECT * FROM mails WHERE LENGTH(txt) < 300 LIMIT 300,1\\G\fR
+*************************** 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)
+.fi
+.RE
+.\" end of SS subsection "Displaying Query Results Vertically"
+.SS "Using the \-\-safe\-updates Option"
+.PP
+For beginners, a useful startup option is
+\fB\-\-safe\-updates\fR
+(or
+\fB\-\-i\-am\-a\-dummy\fR, which has the same effect). It is helpful for cases when you might have issued a
+DELETE FROM \fItbl_name\fR
+statement but forgotten the
+WHERE
+clause. Normally, such a statement deletes all rows from the table. With
+\fB\-\-safe\-updates\fR, you can delete rows only by specifying the key values that identify them. This helps prevent accidents.
+.PP
+When you use the
+\fB\-\-safe\-updates\fR
+option,
+\fBmysql\fR
+issues the following statement when it connects to the MySQL server:
+.sp
+.RS 3n
+.nf
+SET sql_safe_updates=1, sql_select_limit=1000, sql_max_join_size=1000000;
+.fi
+.RE
+.PP
+See
+Section\ 5.1.4, \(lqSession System Variables\(rq.
+.PP
+The
+SET
+statement has the following effects:
+.TP 3n
+\(bu
+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:
+.sp
+.RS 3n
+.nf
+UPDATE \fItbl_name\fR SET \fInot_key_column\fR=\fIval\fR WHERE \fIkey_column\fR=\fIval\fR;
+UPDATE \fItbl_name\fR SET \fInot_key_column\fR=\fIval\fR LIMIT 1;
+.fi
+.RE
+.TP 3n
+\(bu
+The server limits all large
+SELECT
+results to 1,000 rows unless the statement includes a
+LIMIT
+clause.
+.TP 3n
+\(bu
+The server aborts multiple\-table
+SELECT
+statements that probably need to examine more than 1,000,000 row combinations.
+.sp
+.RE
+.PP
+To specify limits different from 1,000 and 1,000,000, you can override the defaults by using the
+\fB\-\-select_limit\fR
+and
+\fB\-\-max_join_size\fR
+options:
+.sp
+.RS 3n
+.nf
+shell> \fBmysql \-\-safe\-updates \-\-select_limit=500 \-\-max_join_size=10000\fR
+.fi
+.RE
+.\" end of SS subsection "Using the \-\-safe\-updates Option"
+.SS "Disabling mysql Auto\-Reconnect"
+.PP
+If the
+\fBmysql\fR
+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
+\fBmysql\fR
+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:
+.sp
+.RS 3n
+.nf
+mysql> \fBSET @a=1;\fR
+Query OK, 0 rows affected (0.05 sec)
+mysql> \fBINSERT INTO t VALUES(@a);\fR
+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> \fBSELECT * FROM t;\fR
++\-\-\-\-\-\-+
+| a    |
++\-\-\-\-\-\-+
+| NULL |
++\-\-\-\-\-\-+
+1 row in set (0.05 sec)
+.fi
+.RE
+.PP
+The
+@a
+user variable has been lost with the connection, and after the reconnection it is undefined. If it is important to have
+\fBmysql\fR
+terminate with an error if the connection has been lost, you can start the
+\fBmysql\fR
+client with the
+\fB\-\-skip\-reconnect\fR
+option.
+.PP
+For more information about auto\-reconnect and its effect on state information when a reconnection occurs, see
+Section\ 21.10.11, \(lqControlling Automatic Reconnection Behavior\(rq.
+.\" end of SS subsection "Disabling mysql Auto\-Reconnect"
+.SH "COPYRIGHT"
+.PP
+Copyright 2007\-2008 MySQL AB, 2009 Sun Microsystems, Inc.
+.PP
+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.
+.PP
+This documentation is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+.PP
+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 http://www.gnu.org/licenses/.
+.SH "REFERENCES"
+.TP 3
+1.\ Bug#25946
+\%http://bugs.mysql.com/25946
+.SH "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/.
+.SH AUTHOR
+MySQL AB (http://www.mysql.com/).