About the mysql command-line client

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:

mysql db_name


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

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

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.

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

mysql db_name < script.sql > output.tab

mysql options

Options can be specified on the command line or in the [mysql], [client], [client-server] or [client-mariadb] option file groups of a my.cnf file. The full list of supported options can be obtained with:

mysql --verbose --help

The following options are available:

-?, --helpDisplay this help and exit.
-I, --helpSynonym for -?
--abort-source-on-errorAbort 'source filename' operations in case of errors.
--auto-rehashEnable automatic rehashing. This option is on by default, which enables database, table, and column name completion. Use --disable-auto-rehash, --no-auto-rehash or skip-auto-rehash to disable rehashing. That causes mysql to start faster, but you must issue the rehash command if you want to use name completion. To complete a name, enter the first part and press Tab. If the name is unambiguous, mysql completes it. Otherwise, you can press Tab again to see the possible names that begin with what you have typed so far. Completion does not occur if there is no default database.
-A, --no-auto-rehashNo automatic rehashing. One has to use 'rehash' to get table and field completion. This gives a quicker start of mysql and disables rehashing on reconnect.
--auto-vertical-outputAutomatically switch to vertical output mode if the result is wider than the terminal width.
-B, --batchPrint results using tab as the column separator, with each row on a new line. With this option, mysql does not use the history file. Batch mode results in nontabular output format and escaping of special characters. Escaping may be disabled by using raw mode; see the description for the --raw option. (Enables --silent.)
--binary-modeBy default, ASCII '\0' is disallowed and '\r\n' is translated to '\n'. This switch turns off both features, and also turns off parsing of all client commands except \C and DELIMITER, in non-interactive mode (for input piped to mysql or loaded using the 'source' command). This is necessary when processing output from mysqlbinlog that may contain blobs.
--character-sets-dir=nameDirectory for character set files.
--column-namesWrite column names in results. (Defaults to on; use --skip-column-names to disable.)
--column-type-infoDisplay column type information.
-c, --commentsPreserve comments. Send comments to the server. The default is --skip-comments (discard comments), enable with --comments.
-C, --compressCompress all information sent between the client and the server if both support compression.
--connect-timeout=numNumber of seconds before connection timeout. Defaults to zero.
-D, --database=nameDatabase to use.
-# [options], --debug[=options]On debugging builds, write a debugging log. A typical debug_options string is d:t:o,file_name. The default is d:t:o,/tmp/mysql.trace.
--debug-checkCheck memory and open file usage at exit.
-T, --debug-infoPrint some debug info at exit.
--default-auth=pluginDefault authentication client-side plugin to use.
--default-character-set=nameSet the default character set. A common issue that can occur when the operating system uses utf8 or another multibyte character set is that output from the mysql client is formatted incorrectly, due to the fact that the MariaDB client uses the latin1 character set by default. You can usually fix such issues by using this option to force the client to use the system character set instead.
--defaults-extra-file=fileRead this file after the global files are read. Must be given as the first option.
--defaults-file=fileOnly read default options from the given file. Must be given as the first option.
--defaults-group-suffix=suffixIn addition to the given groups, also read groups with this suffix.
--delimiter=nameDelimiter to be used. The default is the semicolon character (“;”).
-e, --execute=nameExecute statement and quit. Disables --force and history file. The default output format is like that produced with --batch.
-f, --forceContinue even if we get an SQL error. Sets --abort-source-on-error to 0.
-h, --host=nameConnect to host.
-H, --htmlProduce HTML output.
-U, --i-am-a-dummySynonym for option --safe-updates, -U.
-i, --ignore-spacesIgnore space after function names. Allows one to have spaces (including tab characters and new line characters) between function name and '('. The drawback is that this causes built in functions to become reserved words.
--init-command=strSQL Command to execute when connecting to the MariaDB server. Will automatically be re-executed when reconnecting.
--line-numbersWrite line numbers for errors. (Defaults to on; use --skip-line-numbers to disable.)
--local-infileEnable 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.
--max-allowed-packet=numThe maximum packet length to send to or receive from server. The default is 16MB, the maximum 1GB.
--max-join-size=numAutomatic limit for rows in a join when using --safe-updates. Default is 1000000.
-G, --named-commandsEnable named commands. Named commands mean mysql's internal commands (see below) . When enabled, the named commands can be used from any line of the query, otherwise only from the first line, before an enter. Long-format commands are allowed, not just short-format commands. For example, quit and \q are both recognized. Disable with --disable-named-commands. This option is disabled by default.
--net-buffer-length=numThe buffer size for TCP/IP and socket communication. Default is 16KB.
-b, --no-beepTurn off beep on error.
--no-defaultsDon't read default options from any option file. Must be given as the first option.
-o, --one-databaseIgnore statements except those those that occur while the default database is the one named on the command line. This filtering is limited, and based only on USE statements. This is useful for skipping updates to other databases in the binary log.
--pager[=name]Pager to use to display results (Unix only). If you don't supply an option, the default pager is taken from your ENV variable PAGER. Valid pagers are less, more, cat [> filename], etc. See interactive help (\h) also. This option does not work in batch mode. Disable with --disable-pager. This option is disabled by default.
-p, --password[=name]Password to use when connecting to 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, mysql prompts for one. Specifying a password on the command line should be considered insecure. You can use an option file to avoid giving the password on the command line.
--plugin-dir=nameDirectory for client-side plugins.
-P, --port=numPort number to use for connection or 0 for default to, in order of preference, my.cnf, $MYSQL_TCP_PORT, /etc/services, built-in default (3306).
--print-defaultsPrint the program argument list and exit. Must be given as the first option.
--progress-reportsGet progress reports for long running commands (such as ALTER TABLE). (Defaults to on; use --skip-progress-reports to disable.)
--prompt=nameSet the mysql prompt to this value. See prompt command for options.
--protocol=nameThe protocol to use for connection (tcp, socket, pipe, memory).
-q, --quickDon't cache result, print it row by row. This may slow down the server if the output is suspended. Doesn't use history file.
-r, --rawFor tabular output, the “boxing” around columns enables one column value to be distinguished from another. For nontabular output (such as is produced in batch mode or when the --batch or --silent option is given), special characters are escaped in the output so they can be identified easily. Newline, tab, NUL, and backslash are written as \n, \t, \0, and
. The --raw option disables this character escaping.
--reconnectReconnect if the connection is lost. This option is enabled by default. Disable with --disable-reconnect or skip-reconnect.
-U, --safe-updatesAllow 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 using the --safe-updates option for more.
--secure-authRefuse client connecting to server if it uses old (pre-MySQL4.1.1) protocol. Defaults to false (unlike MySQL since 5,6, which defaults to true).
--select-limit=numAutomatic limit for SELECT when using --safe-updates. Default 1000.
--server-arg=nameSend embedded server this as a parameter.
--shared-memory-base-name=nameShared-memory name to use for Windows connections using shared memory to a local server (started with the --shared-memory option). Case-sensitive.
--show-warningsShow warnings after every statement. Applies to interactive and batch mode.
--sigint-ignoreIgnore SIGINT signals (usually CTRL-C).
-s, --silentBe more silent. This option can be given multiple times to produce less and less output. This option results in nontabular output format and escaping of special characters. Escaping may be disabled by using raw mode; see the description for the --raw option.
-L, --skip-auto-rehashDon't write line number for errors. See --auto-rehash.
-N, --skip-column-namesDon't write column names in results. See --column-names.
-L, --skip-commentsDon't write line number for errors. See --comments.
-L, --skip-line-numbersDon't write line number for errors. See --line-numbers.
-L, --skip-progress-reportsDon't write line number for errors. See --progress-reports.
-L, --skip-reconnectDon't write line number for errors. See --reconnect.
-S, --socket=nameFor connections to localhost, the Unix socket file to use, or, on Windows, the name of the named pipe to use.
--sslEnable SSL for connection (automatically enabled with other flags).
--ssl-ca=nameCA file in PEM format (check OpenSSL docs, implies --ssl).
--ssl-capath=nameCA directory (check OpenSSL docs, implies --ssl).
--ssl-cert=nameX509 cert in PEM format (implies --ssl).
--ssl-cipher=nameSSL cipher to use (implies --ssl).
--ssl-key=nameX509 key in PEM format (implies --ssl).
--ssl-crl=nameCertificate revocation list (implies --ssl).
--ssl-crlpath=nameCertificate revocation list path (implies --ssl).
--ssl-verify-server-certVerify server's "Common Name" in its cert against hostname used when connecting. This option is disabled by default.
-t, --tableDisplay output in table format. This is the default for interactive use, but can be used to produce table output in batch mode.
--tee=nameAppend everything into outfile. See interactive help (\h) also. Does not work in batch mode. Disable with --disable-tee. This option is disabled by default.
-n, --unbufferedFlush buffer after each query.
-u, --user=nameUser for login if not current user.
-v, --verboseWrite more. (-v -v -v gives the table output format).
-V, --versionOutput version information and exit.
-E, --verticalPrint the output of a query (rows) vertically. Use the \G delimiter to apply to a particular statement if this option is not enabled.
-w, --waitIf the connection cannot be established, wait and retry instead of aborting.
-X, --xmlProduce XML output. See the mysqldump --xml option for more.

Default options are read from the following files in the given order: /etc/my.cnf /etc/mysql/my.cnf /.my.cnf The following groups are read: mysql client client-server client-mariadb

The output you get when running the above may differ depending on any customizations you may have in your local my.cnf file. See Configuring MariaDB with my.cnf.

mysql commands

There are also a number of commands that can be run inside the client. Note that all text commands must be first on line and end with ';'

?, \?Synonym for `help'.
clear, \cClear the current input statement.
connect, \rReconnect to the server. Optional arguments are db and host.
delimiter, \dSet statement delimiter.
edit, \eEdit command with $EDITOR.
ego, \GSend command to mysql server, display result vertically.
exit, \qExit mysql. Same as quit.
go, \gSend command to mysql server.
help, \hDisplay this help.
nopager, \nDisable pager, print to stdout.
notee, \tDon't write into outfile.
pager, \PSet PAGER [to_pager]. Print the query results via PAGER.
print, \pPrint current command.
prompt, \RChange your mysql prompt. See prompt command for options.
quit, \qQuit mysql.
rehash, \# Rebuild completion hash.
source, \.Execute an SQL script file. Takes a file name as an argument.
status, \sGet status information from the server.
system, \!Execute a system shell command.
tee, \TSet outfile [to_outfile]. Append everything into given outfile.
use, \uUse another database. Takes database name as argument.
charset, \CSwitch to another charset. Might be needed for processing binlog with multi-byte charsets.
warnings, \WShow warnings after every statement.
nowarning, \wDon't show warnings after every statement.

The mysql_history file

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

The .mysql_history file 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.

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.

prompt command

The prompt command reconfigures the default prompt \N [\d]>. The string for defining the prompt can contain the following special sequences.

\cA counter that increments for each statement you issue.
\DThe full current date.
\dThe default database.
\hThe server host.
\lThe current delimiter.
\mMinutes of the current time.
\nA newline character.
\OThe current month in three-letter format (Jan, Feb, ...).
\oThe current month in numeric format.
\pThe current TCP/IP port or socket file.
\RThe current time, in 24-hour military time (0–23).
\rThe current time, standard 12-hour time (1–12).
\sSeconds of the current time.
\tA tab character.
\UYour full user_name@host_name account name.
\uYour user name.
\vThe server version.
\wThe current day of the week in three-letter format (Mon, Tue, ...).
\YThe current year, four digits.
\yThe current year, two digits.
\_A space.
\A space (a space follows the backslash).
\Single quote.
\"Double quote.
\ \A literal “\” backslash character.
\xx, for any “x” not listed above.

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.
    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 MariaDB server:

SET sql_safe_updates=1, sql_select_limit=1000, sql_max_join_size=1000000;

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 largeSELECT 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:

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 |

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.


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