Difference between revisions of "The mysql Command-Line Tool"

Revision as of 14:44, 5 May 2016

In MySQL Database Architecture we covered the fact that MySQL is a client-server based database management system (DBMS). In this chapter we will begin by looking at the mysql client tool, arguably the most valuable of the client tools provided with MySQL. In the following chapters the MySQL Administrator and MySQL Browser tools will also be detailed.

The mysql Command-line Utility

The mysql tool is probably the most useful utility and is the tool that you will likely use the most as you learn and continue to use MySQL. mysql is a command-line client tool that is installed as standard with the MySQL package. From the mysql command-prompt it is possible to issue a wide range of commands to the database server such as creating and deleting databases and tables, searching for data, adding new rows and much more. Throughout this book the capabilities of the mysql tool will be covered in great detail.

Assuming MySQL has been installed the mysql tool may be loaded at the operating system command-prompt as follows:

mysql

The above command will display the following output:

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 234343 to server version: 5.0.27

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql>

If you see an error message, it may be that your database system is configured to require login credentials, or that the server is running on a different system. For example, if your database server requires a username and password to gain access the -u and -p command-line options may be used respectively:

mysql -u john -p

The above command will prompt for the password for user john before allowing access to the database management system.

If the mysql client is running a different system to the MySQL server, the -h flag may be used to specify the name of the remote host together with -P to specify the port:

mysql -h myDBServer -p 5678

A list of command-line options can be obtained running mysql --help at the command-prompt (listed below).

Once mysql is running, commands are entered at the mysql> prompt. Typing help at this prompt will display a list of the commands supported by the tool (listed below).

Commands are terminated by a semi-colon (;). If a command is not terminated by a semi-colon, pressing enter simply continues the current command on the following line.

To exit from mysql type quit at the mysql> command-prompt.

mysql Command-Line Arguments

Usage: mysql [OPTIONS] [database]
  -?, --help          Display this help and exit.
  -I, --help          Synonym for -?
  --auto-rehash       Enable automatic rehashing. One doesn't need to use
                      'rehash' to get table and field completion, but startup
                      and reconnecting may take a longer time. Disable with
                      --disable-auto-rehash.
  -A, --no-auto-rehash
                      No 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. WARNING:
                      options deprecated; use --disable-auto-rehash instead.
  -B, --batch         Don't use history file. Disable interactive behavior.
                      (Enables --silent)
  --character-sets-dir=name
                      Directory where character sets are.
  --default-character-set=name
                      Set the default character set.
  -C, --compress      Use compression in server/client protocol.
  -#, --debug[=#]     This is a non-debug version. Catch this and exit
  -D, --database=name Database to use.
  --delimiter=name    Delimiter to be used.
  -e, --execute=name  Execute command and quit. (Disables --force and history
                      file)
  -E, --vertical      Print the output of a query (rows) vertically.
  -f, --force         Continue even if we get an sql error.
  -G, --named-commands
                      Enable named commands. Named commands mean this program's
                      internal commands; see mysql> help . When enabled, the
                      named commands can be used from any line of the query,
                      otherwise only from the first line, before an enter.
                      Disable with --disable-named-commands. This option is
                      disabled by default.
  -g, --no-named-commands
                      Named commands are disabled. Use \* form only, or use
                      named commands only in the beginning of a line ending
                      with a semicolon (;) Since version 10.9 the client now
                      starts with this option ENABLED by default! Disable with
                      '-G'. Long format commands still work from the first
                      line. WARNING: option deprecated; use
                      --disable-named-commands instead.
  -i, --ignore-spaces Ignore space after function names.
  --local-infile      Enable/disable LOAD DATA LOCAL INFILE.
  -b, --no-beep       Turn off beep on error.
  -h, --host=name     Connect to host.
  -H, --html          Produce HTML output.
  -X, --xml           Produce XML output
  --line-numbers      Write line numbers for errors.
  -L, --skip-line-numbers
                      Don't write line number for errors. WARNING: -L is
                      deprecated, use long version of this option instead.
  -n, --unbuffered    Flush buffer after each query.
  --column-names      Write column names in results.
  -N, --skip-column-names
                      Don't write column names in results. WARNING: -N is
                      deprecated, use long version of this options instead.
  -O, --set-variable=name
                      Change the value of a variable. Please note that this
                      option is deprecated; you can set variables directly with
                      --variable-name=value.
  --sigint-ignore     Ignore SIGINT (CTRL-C)
  -o, --one-database  Only update the default database. This is useful for
                      skipping updates to other database in the update log.
  --pager[=name]      Pager to use to display results. 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.
  --no-pager          Disable pager and print to stdout. See interactive help
                      (\h) also. WARNING: option deprecated; use
                      --disable-pager instead.
  -p, --password[=name]
                      Password to use when connecting to server. If password is
                      not given it's asked from the tty.
  -P, --port=#        Port number to use for connection.
  --prompt=name       Set the mysql prompt to this value.
  --protocol=name     The protocol of connection (tcp,socket,pipe,memory).
  -q, --quick         Don'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, --raw           Write fields without conversion. Used with --batch.
  --reconnect         Reconnect if the connection is lost. Disable with
                      --disable-reconnect. This option is enabled by default.
  -s, --silent        Be more silent. Print results with a tab as separator,
                      each row on new line.
  -S, --socket=name   Socket file to use for connection.
  --ssl               Enable SSL for connection (automatically enabled with
                      other flags). Disable with --skip-ssl.
  --ssl-ca=name       CA file in PEM format (check OpenSSL docs, implies
                      --ssl).
  --ssl-capath=name   CA directory (check OpenSSL docs, implies --ssl).
  --ssl-cert=name     X509 cert in PEM format (implies --ssl).
  --ssl-cipher=name   SSL cipher to use (implies --ssl).
  --ssl-key=name      X509 key in PEM format (implies --ssl).
  --ssl-verify-server-cert
                      Verify server's "Common Name" in its cert against
                      hostname used when connecting. This option is disabled by
                      default.
  -t, --table         Output in table format.
  -T, --debug-info    Print some debug info at exit.
  --tee=name          Append everything into outfile. See interactive help (\h)
                      also. Does not work in batch mode. Disable with
                      --disable-tee. This option is disabled by default.
  --no-tee            Disable outfile. See interactive help (\h) also. WARNING:
                      option deprecated; use --disable-tee instead
  -u, --user=name     User for login if not current user.
  -U, --safe-updates  Only allow UPDATE and DELETE that uses keys.
  -U, --i-am-a-dummy  Synonym for option --safe-updates, -U.
  -v, --verbose       Write more. (-v -v -v gives the table output format).
  -V, --version       Output version information and exit.
  -w, --wait          Wait and retry if connection is down.
  --connect_timeout=# Number of seconds before connection timeout.
  --max_allowed_packet=#
                      Max packet length to send to, or receive from server
  --net_buffer_length=#
                      Buffer for TCP/IP and socket communication
  --select_limit=#    Automatic limit for SELECT when using --safe-updates
  --max_join_size=#   Automatic limit for rows in a join when using
                      --safe-updates
  --secure-auth       Refuse client connecting to server if it uses old
                      (pre-4.1.1) protocol
  --show-warnings     Show warnings after every statement.

Default options are read from the following files in the given order:
/etc/my.cnf ~/.my.cnf /etc/my.cnf
The following groups are read: mysql client
The following options may be given as the first argument:
--print-defaults        Print the program argument list and exit
--no-defaults           Don't read default options from any options file
--defaults-file=#       Only read default options from the given file #
--defaults-extra-file=# Read this file after the global files are read

Variables (--variable-name=value)
and boolean options {FALSE|TRUE}  Value (after reading options)
--------------------------------- -----------------------------
auto-rehash                       TRUE
character-sets-dir                (No default value)
default-character-set             latin1
compress                          FALSE
database                          (No default value)
delimiter                         ;
vertical                          FALSE
force                             FALSE
named-commands                    FALSE
local-infile                      FALSE
no-beep                           FALSE
host                              (No default value)
html                              FALSE
xml                               FALSE
line-numbers                      TRUE
unbuffered                        FALSE
column-names                      TRUE
sigint-ignore                     FALSE
port                              0
prompt                            mysql>
quick                             FALSE
raw                               FALSE
reconnect                         TRUE
socket                            (No default value)
ssl                               FALSE
ssl-ca                            (No default value)
ssl-capath                        (No default value)
ssl-cert                          (No default value)
ssl-cipher                        (No default value)
ssl-key                           (No default value)
ssl-verify-server-cert            FALSE
table                             FALSE
debug-info                        FALSE
user                              (No default value)
safe-updates                      FALSE
i-am-a-dummy                      FALSE
connect_timeout                   0
max_allowed_packet                16777216
net_buffer_length                 16384
select_limit                      1000
max_join_size                     1000000
secure-auth                       FALSE
show-warnings                     FALSE

mysql Commands

The following commands are supported at the mysql> prompt:

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. 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.

Summary

This chapter has covered the basics of the mysql command line tool.