.\" ** You probably do not want to edit this file directly **
.\" It was generated using the DocBook XSL Stylesheets (version 1.69.1).
.\" Instead of manually editing it, you probably should edit the DocBook XML
.\" source for it and then use the DocBook XSL Stylesheets to regenerate it.
.TH "\\FBMYSQL\\FR" "1" "07/19/2006" "MySQL 4.1" "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
.nf
shell> \fBmysql \fR\fB\fIdb_name\fR\fR
.fi
.PP
Or:
.sp
.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
.PP
Then type an SQL statement, end it with \(oq;\(cq,
\\g, or
\\G
and press Enter.
.PP
You can execute SQL statements in a script file (batch file) like this:
.sp
.nf
shell> \fBmysql \fR\fB\fIdb_name\fR\fR\fB < \fR\fB\fIscript.sql\fR\fR\fB > \fR\fB\fIoutput.tab\fR\fR
.fi
.SH "\\FBMYSQL\\FR OPTIONS"
.PP
\fBmysql\fR
supports the following options:
.TP 3
\(bu
\fB\-\-help\fR,
\fB\-?\fR
.sp
Display a help message and exit.
.TP
\(bu
\fB\-\-auto\-rehash\fR
.sp
Enable automatic rehashing. This option is on by default, which enables table and column name completion. Use
\fB\-\-skip\-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 table and column name completion.
.TP
\(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.
.TP
\(bu
\fB\-\-character\-sets\-dir=\fR\fB\fIpath\fR\fR
.sp
The directory where character sets are installed. See
Section\ 9.1, \(lqThe Character Set Used for Data and Sorting\(rq.
.TP
\(bu
\fB\-\-column\-names\fR
.sp
Write column names in results.
.TP
\(bu
\fB\-\-compress\fR,
\fB\-C\fR
.sp
Compress all information sent between the client and the server if both support compression.
.TP
\(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
\(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
\(bu
\fB\-\-debug\-info\fR,
\fB\-T\fR
.sp
Print some debugging information when the program exits.
.TP
\(bu
\fB\-\-default\-character\-set=\fR\fB\fIcharset_name\fR\fR
.sp
Use
\fIcharset_name\fR
as the default character set. See
Section\ 9.1, \(lqThe Character Set Used for Data and Sorting\(rq.
.TP
\(bu
\fB\-\-delimiter=\fR\fB\fIstr\fR\fR
.sp
Set the statement delimiter. The default is the semicolon character (\(oq;\(cq).
.TP
\(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\ 3.1, \(lqUsing Options on the Command Line\(rq, for some examples.
.TP
\(bu
\fB\-\-force\fR,
\fB\-f\fR
.sp
Continue even if an SQL error occurs.
.TP
\(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
\(bu
\fB\-\-html\fR,
\fB\-H\fR
.sp
Produce HTML output.
.TP
\(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
the section called \(lqTHE SERVER SQL MODE\(rq).
.TP
\(bu
\fB\-\-line\-numbers\fR
.sp
Write line numbers for errors. Disable this with
\fB\-\-skip\-line\-numbers\fR.
.TP
\(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
\(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
\(bu
\fB\-\-no\-auto\-rehash\fR,
\fB\-A\fR
.sp
Deprecated form of
\fB\-skip\-auto\-rehash\fR. See the description for
\fB\-\-auto\-rehash\fR.
.TP
\(bu
\fB\-\-no\-beep\fR,
\fB\-b\fR
.sp
Do not beep when errors occur.
.TP
\(bu
\fB\-\-no\-named\-commands\fR,
\fB\-g\fR
.sp
Disable named commands. Use the
\\*
form only, or use named commands only at the beginning of a line ending with a semicolon (\(oq;\(cq). As of MySQL 3.23.22,
\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
\(bu
\fB\-\-no\-pager\fR
.sp
Deprecated form of
\fB\-\-skip\-pager\fR. See the
\fB\-\-pager\fR
option.
.TP
\(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
\(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
\(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
\(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\ 7.6, \(lqKeeping Your Password Secure\(rq.
.TP
\(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
\(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
\(bu
\fB\-\-protocol={TCP|SOCKET|PIPE|MEMORY}\fR
.sp
The connection protocol to use. Added in MySQL 4.1.
.TP
\(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
\(bu
\fB\-\-raw\fR,
\fB\-r\fR
.sp
Write column values without escape conversion. Often used with the
\fB\-\-batch\fR
option.
.TP
\(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. Added in MySQL 4.1.0.
.TP
\(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
\(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. This option was added in MySQL 4.1.1.
.TP
\(bu
\fB\-\-sigint\-ignore\fR
.sp
Ignore
SIGINT
signals (typically the result of typing Control\-C). This option was added in MySQL 4.1.6.
.TP
\(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.
.TP
\(bu
\fB\-\-skip\-column\-names\fR,
\fB\-N\fR
.sp
Do not write column names in results.
.TP
\(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.
.TP
\(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
\(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\ 7.7.3, \(lqSSL Command Options\(rq.
.TP
\(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
\(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. in
the section called \(lq\\FBMYSQL\\FR COMMANDS\(rq, discusses tee files further.
.TP
\(bu
\fB\-\-unbuffered\fR,
\fB\-n\fR
.sp
Flush the buffer after each query.
.TP
\(bu
\fB\-\-user=\fR\fB\fIuser_name\fR\fR,
\fB\-u \fR\fB\fIuser_name\fR\fR
.sp
The MySQL username to use when connecting to the server.
.TP
\(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
\(bu
\fB\-\-version\fR,
\fB\-V\fR
.sp
Display version information and exit.
.TP
\(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
\(bu
\fB\-\-wait\fR,
\fB\-w\fR
.sp
If the connection cannot be established, wait and retry instead of aborting.
.TP
\(bu
\fB\-\-xml\fR,
\fB\-X\fR
.sp
Produce XML output.
.PP
You can also set the following variables by using
\fB\-\-\fR\fB\fIvar_name\fR\fR\fB=\fR\fB\fIvalue\fR\fR
syntax:
.TP 3
\(bu
connect_timeout
.sp
The number of seconds before connection timeout. (Default value is
0.)
.TP
\(bu
max_allowed_packet
.sp
The maximum packet length to send to or receive from the server. (Default value is 16MB.)
.TP
\(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
\(bu
net_buffer_length
.sp
The buffer size for TCP/IP and socket communication. (Default value is 16KB.)
.TP
\(bu
select_limit
.sp
The automatic limit for
SELECT
statements when using
\fB\-\-safe\-updates\fR. (Default value is 1,000.)
.PP
It is also possible to set variables by using
\fB\-\-set\-variable=\fR\fB\fIvar_name\fR\fR\fB=\fR\fB\fIvalue\fR\fR
or
\fB\-O \fR\fB\fIvar_name\fR\fR\fB=\fR\fB\fIvalue\fR\fR
syntax. In MySQL 4.1, this syntax is deprecated.
.PP
On Unix, the
\fBmysql\fR
client writes a record of executed statements to a history file. By default, the history 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
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 3
\(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
\(bu
Create
\fI.mysql_history\fR
as a symbolic link to
\fI/dev/null\fR:
.sp
.nf
shell> \fBln \-s /dev/null $HOME/.mysql_history\fR
.fi
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
.nf
mysql> \fBhelp\fR
MySQL commands:
?         (\\?) Synonym for `help'.
clear     (\\c) Clear command.
connect   (\\r) Reconnect to the server. Optional arguments are db and host.
delimiter (\\d) Set statement delimiter. NOTE: Takes the rest of the line as
               new delimiter.
edit      (\\e) Edit command with $EDITOR.
ego       (\\G) Send command to mysql server, display result vertically.
exit      (\\q) Exit mysql. Same as quit.
go        (\\g) Send command to mysql server.
help      (\\h) Display this help.
nopager   (\\n) Disable pager, print to stdout.
notee     (\\t) Don't write into outfile.
pager     (\\P) Set PAGER [to_pager]. Print the query results via PAGER.
print     (\\p) Print current command.
prompt    (\\R) Change your mysql prompt.
quit      (\\q) Quit mysql.
rehash    (\\#) Rebuild completion hash.
source    (\\.) Execute 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
.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
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.
.PP
In the
delimiter
command, you should avoid the use of the backslash (\(oq\\\(cq) character because that is the escape character for MySQL.
.PP
The
\fBedit\fR,
\fBnopager\fR,
\fBpager\fR, and
\fBsystem\fR
commands work only in Unix.
.PP
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.
.PP
To log queries and their output, use the
\fBtee\fR
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
\fB\-\-tee\fR
option, or interactively with the
\fBtee\fR
command. The
\fBtee\fR
file can be disabled interactively with the
\fBnotee\fR
command. Executing
\fBtee\fR
again re\-enables logging. Without a parameter, the previous file is used. Note that
\fBtee\fR
flushes query results to the file after each statement, just before
\fBmysql\fR
prints its next prompt.
.PP
By using the
\fB\-\-pager\fR
option, 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. 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.
.PP
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 this is not as convenient as
\fBpager\fR
for browsing output in some situations.
.PP
Here are a few tips about the
\fBpager\fR
command:
.TP 3
\(bu
You can use it to write to a file and the results go only to the file:
.sp
.nf
mysql> \fBpager cat > /tmp/log.txt\fR
.fi
You can also pass any options for the program that you want to use as your pager:
.sp
.nf
mysql> \fBpager less \-n \-i \-S\fR
.fi
.TP
\(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
.nf
shell> \fBman less\fR
.fi
.TP
\(bu
You can specify very complex pager commands for handling query output:
.sp
.nf
mysql> \fBpager cat | tee /dr1/tmp/res.txt \\\fR
          \fB| tee /dr2/tmp/res2.txt | less \-n \-i \-S\fR
.fi
In this example, the command would send query results to two files in two different directories on two different filesystems mounted on
\fI/dr1\fR
and
\fI/dr2\fR, yet still display the results onscreen via
\fBless\fR.
.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
From MySQL 4.0.2 on, the default
mysql>
prompt can be reconfigured. The string for defining the prompt can contain the following special sequences:
\fBOption\fR\fBDescription\fR\\vThe server version\\dThe default database\\hThe server host\\pThe current TCP/IP port or socket file\\uYour username\\UYour full
                  \fIuser_name\fR@\fIhost_name\fR
                  account name\\\\A literal \(oq\\\(cq backslash character\\nA newline character\\tA tab character\\ A space (a space follows the backslash)\\_A space\\RThe current time, in 24\-hour military time (0\-23)\\rThe current time, standard 12\-hour time (1\-12)\\mMinutes of the current time\\yThe current year, two digits\\YThe current year, four digits\\DThe full current date\\sSeconds of the current time\\wThe current day of the week in three\-letter format (Mon, Tue, \&...)\\Pam/pm\\oThe current month in numeric format\\OThe current month in three\-letter format (Jan, Feb, \&...)\\cA counter that increments for each statement you issue\\SSemicolon\\'Single quote\\"Double quote.PP
\(oq\\\(cq followed by any other letter just becomes that letter.
.PP
If you specify the
prompt
command with no argument,
\fBmysql\fR
resets the prompt to the default of
mysql>.
.PP
You can set the prompt in several ways:
.TP 3
\(bu
\fIUse an environment variable.\fR
You can set the
MYSQL_PS1
environment variable to a prompt string. For example:
.sp
.nf
shell> \fBexport MYSQL_PS1="(\\u@\\h) [\\d]> "\fR
.fi
.TP
\(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
.nf
shell> \fBmysql \-\-prompt="(\\u@\\h) [\\d]> "\fR
(user@host) [database]>
.fi
.TP
\(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
.nf
[mysql]
prompt=(\\\\u@\\\\h) [\\\\d]>\\\\_
.fi
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, \(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
.nf
[mysql]
prompt="\\\\r:\\\\m:\\\\s> "
.fi
.TP
\(bu
\fISet the prompt interactively.\fR
You can change your prompt interactively by using the
prompt
(or
\\R) command. For example:
.sp
.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
.TP
\(bu
.SH "\\FBMYSQL\\FR SERVER\-SIDE HELP"
.sp
.nf
mysql> \fBhelp \fR\fB\fIsearch_string\fR\fR
.fi
.PP
As of MySQL 4.1, 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
the section called \(lqMYSQL SERVER\-SIDE HELP SUPPORT\(rq).
.PP
If there is no match for the search string, the search fails:
.sp
.nf
mysql> \fBhelp me\fR
Nothing found
Please try to run 'help contents' for a list of all accessible topics
.fi
.PP
Use
\fBhelp contents\fR
to see a list of the help categories:
.sp
.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
   Storage Engines
   Table Maintenance
   Transactions
.fi
.PP
If the search string matches multiple items,
\fBmysql\fR
shows a list of matching topics:
.sp
.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
.PP
Use a topic as the search string to see the help entry for that topic:
.sp
.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\-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 |
+\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-+\-\-\-\-\-\-\-\-\-\-\-+
.fi
.SH "EXECUTING SQL STATEMENTS FROM A TEXT FILE"
.PP
The
\fBmysql\fR
client typically is used interactively, like this:
.sp
.nf
shell> \fBmysql \fR\fB\fIdb_name\fR\fR
.fi
.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
.nf
shell> \fBmysql \fR\fB\fIdb_name\fR\fR\fB < \fR\fB\fItext_file\fR\fR
.fi
.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
.nf
shell> \fBmysql < text_file\fR
.fi
.PP
If you are already running
\fBmysql\fR, you can execute an SQL script file using the
source
or
\\.
command:
.sp
.nf
mysql> \fBsource \fR\fB\fIfile_name\fR\fR
mysql> \fB\\. \fR\fB\fIfile_name\fR\fR
.fi
.PP
Sometimes you may want your script to display progress information to the user. For this you can insert statements like this:
.sp
.nf
SELECT '<info_to_display>' AS ' ';
.fi
.PP
The statement shown outputs
<info_to_display>.
.PP
For more information about batch mode, see
Section\ 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
.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
.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). This option was introduced in MySQL 3.23.11. 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
.nf
SET SQL_SAFE_UPDATES=1,SQL_SELECT_LIMIT=1000, SQL_MAX_JOIN_SIZE=1000000;
.fi
.PP
See
Section\ 5.3, \(lqSET Syntax\(rq.
.PP
The
SET
statement has the following effects:
.TP 3
\(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
.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
.TP
\(bu
The server limits all large
SELECT
results to 1,000 rows unless the statement includes a
LIMIT
clause.
.TP
\(bu
The server aborts multiple\-table
SELECT
statements that probably need to examine more than 1,000,000 row combinations.
.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
.nf
shell> \fBmysql \-\-safe\-updates \-\-select_limit=500 \-\-max_join_size=10000\fR
.fi
.SS "Disabling mysql Auto\-Reconnect"
.PP
If the
\fBmysql\fR
client loses its connection to the server while sending a query, it immediately and automatically tries to reconnect once to the server and send the query again. However, even if
\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 without you knowing it:
.sp
.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
.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.
.SH "SEE ALSO"
isamchk(1),
isamlog(1),
msql2mysql(1),
myisam_ftdump(1),
myisamchk(1),
myisamlog(1),
myisampack(1),
mysql.server(1),
mysql_config(1),
mysql_explain_log(1),
mysql_fix_privilege_tables(1),
mysql_zap(1),
mysqlaccess(1),
mysqladmin(1),
mysqlbinlog(1),
mysqlcheck(1),
mysqld(1),
mysqld_multi(1),
mysqld_safe(1),
mysqldump(1),
mysqlhotcopy(1),
mysqlimport(1),
mysqlshow(1),
pack_isam(1),
perror(1),
replace(1),
safe_mysqld(1)
.P
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/).
This software comes with no warranty.