MySQL IN operator

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 – Man Page

mysql is a simple SQL shell with input line editing capabilities. It supports interactive and noninteractive use. When used interactively, query results are presented in an ASCII-table format. When used noninteractively (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().

Note

Alternatively, MySQL Shell offers access to the X DevAPI. For details, see MySQL Shell 8.0 [1] .

Using mysql is very easy. Invoke it from the prompt of your command interpreter as follows:

mysql db_name

mysql --user=user_name --password db_name

In this case, you’ll need to enter your password in response to the prompt that mysql displays:

Enter password: your_password

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

Typing Control+C interrupts the current statement if there is one, or cancels any partial input line otherwise.

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

mysql db_name < script.sql > output.tab

On Unix, the mysql client logs statements executed interactively to a history file. See the section called “MySQL Client Logging”.

MySQL Client Options

mysql supports the following options, which can be specified on the command line or in the [mysql] and [client] groups of an option file. For information about option files used by MySQL programs, see Section 4.2.2.2, “Using Option Files”.

–help, -? Display a help message and exit.
–auto-rehash Enable automatic rehashing. This option is on by default, which enables database, table, and column name completion. Use –disable-auto-rehash to disable rehashing. That causes mysql to start faster, but you must issue the rehash command or its \# shortcut 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.

Note
This feature requires a MySQL client that is compiled with the readline library. Typically, the readline library is not available on Windows.

–binary-as-hex

mysql> SELECT CHAR(0x41), UNHEX('41'); +------------+-------------+ | CHAR(0x41) | UNHEX('41') | +------------+-------------+ | A | A | +------------+-------------+

mysql> SELECT CHAR(0x41), UNHEX('41'); +------------------------+--------------------------+ | CHAR(0x41) | UNHEX('41') | +------------------------+--------------------------+ | 0x41 | 0x41 | +------------------------+--------------------------+

To write a binary string expression so that it displays as a character string regardless of whether –binary-as-hex is enabled, use these techniques:

charset

mysql> SELECT CHAR(0x41 USING utf8mb4); +--------------------------+ | CHAR(0x41 USING utf8mb4) | +--------------------------+ | A | +--------------------------+

mysql> SELECT CONVERT(UNHEX('41') USING utf8mb4); +------------------------------------+ | CONVERT(UNHEX('41') USING utf8mb4) | +------------------------------------+ | A | +------------------------------------+

As of MySQL 8.0.19, when mysql operates in interactive mode, this option is enabled by default. In addition, output from the status (or \s) command includes this line when the option is enabled implicitly or explicitly:

Binary data as: Hexadecimal

To disable hexadecimal notation, use –skip-binary-as-hex

Note
The mysql client always passes optimizer hints to the server, regardless of whether this option is given. Comment stripping is deprecated. Expect this feature and the options to control it to be removed in a future MySQL release.

Name TTL Class Priority Weight Port Target _mysql._tcp.example.com. 86400 IN SRV 0 5 3306 host1.example.com _mysql._tcp.example.com. 86400 IN SRV 0 10 3306 host2.example.com _mysql._tcp.example.com. 86400 IN SRV 10 5 3306 host3.example.com _mysql._tcp.example.com. 86400 IN SRV 20 5 3306 host4.example.com

To use that DNS SRV record, invoke mysql like this:

mysql --dns-srv-name=_mysql._tcp.example.com

mysql --user=user_name --fido-register-factor=3

An account that requires registration for a 2nd and 3rd authentication factor invokes the mysql client as follows:

mysql --user=user_name --fido-register-factor=2,3

If registration is successful, a connection is established. If there is an authentication factor with a pending registration, a connection is placed into pending registration mode when attempting to connect to the server. In this case, disconnect and reconnect with the correct –fido-register-factor value to complete the registration. Registration is a two step process comprising initiate registration and finish registration steps. The initiate registration step executes this statement:

ALTER USER user factor INITIATE REGISTRATION

The statement returns a result set containing a 32 byte challenge, the user name, and the relying party ID (see authentication_fido_rp_id). The finish registration step executes this statement:

ALTER USER user factor FINISH REGISTRATION SET CHALLENGE_RESPONSE AS 'auth_string'

If LOCAL data loading is enabled, either by default in the MySQL client library or by specifying –local-infile[=1], the –load-data-local-dir option is ignored.
If LOCAL data loading is disabled, either by default in the MySQL client library or by specifying –local-infile=0, the –load-data-local-dir option applies.

When –load-data-local-dir applies, the option value designates the directory in which local data files must be located. Comparison of the directory path name and the path name of files to be loaded is case-sensitive regardless of the case sensitivity of the underlying file system. If the option value is the empty string, it names no directory, with the result that no files are permitted for local data loading.

For example, to explicitly disable local data loading except for files located in the /my/local/data directory, invoke mysql like this:

mysql --local-infile=0 --load-data-local-dir=/my/local/data

When both –local-infile and –load-data-local-dir are given, the order in which they are given does not matter.

Successful use of LOCAL load operations within mysql also requires that the server permits local loading; see Section 6.1.6, “Security Considerations for LOAD DATA LOCAL”

The –load-data-local-dir option was added in MySQL 8.0.21.

DELETE FROM db2.t2; USE db2; DROP TABLE db1.t1; CREATE TABLE db1.t1 (i INT); USE db1; INSERT INTO t1 (i) VALUES(1); CREATE TABLE db2.t1 (j INT);

The DELETE statement is executed because the default database is db1, even though the statement names a table in a different database.
The DROP TABLE and CREATE TABLE statements are not executed because the default database is not db1, even though the statements name a table in db1.
The INSERT and CREATE TABLE statements are executed because the default database is db1, even though the CREATE TABLE statement names a table in a different database.

% mysql mysql> SELECT CHAR(92); +----------+ | CHAR(92) | +----------+ | \ | +----------+ % mysql -s mysql> SELECT CHAR(92); CHAR(92) \\ % mysql -s -r mysql> SELECT CHAR(92); CHAR(92) \

OFF: Disable FIPS mode.
ON: Enable FIPS mode.
STRICT: Enable “strict” FIPS mode.

Note
If the OpenSSL FIPS Object Module is not available, the only permitted value for –ssl-fips-mode is OFF. In this case, setting –ssl-fips-mode to ON or STRICT causes the client to produce a warning at startup and to operate in non-FIPS mode.

Mar 7 12:39:25 myhost MysqlClient[20824]: SYSTEM_USER:'oscar', MYSQL_USER:'my_oscar', CONNECTION_ID:23, DB_SERVER:'127.0.0.1', DB:'--', QUERY:'USE test;' Mar 7 12:39:28 myhost MysqlClient[20824]: SYSTEM_USER:'oscar', MYSQL_USER:'my_oscar', CONNECTION_ID:23, DB_SERVER:'127.0.0.1', DB:'test', QUERY:'SHOW TABLES;'

NULL

The output when –xml is used with mysql matches that of mysqldump –xml. See mysqldump(1), for details. The XML output also uses an XML namespace, as shown here:

$> mysql --xml -uroot -e "SHOW VARIABLES LIKE 'version%'"   version 5.0.40-debug  version_comment Source distribution  version_compile_machine i686  version_compile_os suse-linux-gnu

MySQL Client Commands

mysql sends each SQL statement that you issue to the server to be executed. There is also a set of commands that mysql itself interprets. For a list of these commands, type help or \h at the mysql> prompt:

mysql> help List of all MySQL commands: Note that all text commands must be first on line and end with ';' ? (\?) Synonym for `help'. clear (\c) Clear the current input statement. 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. resetconnection(\x) Clean session context. query_attributes Sets string parameters (name1 value1 name2 value2 . ) for the next query to pick up. ssl_session_data_print Serializes the current SSL session data to stdout or file. For server side help, type 'help contents'

If mysql is invoked with the –binary-mode option, all mysql commands are disabled except charset and delimiter in noninteractive mode (for input piped to mysql or loaded using the source command).

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.

The use of short-form commands within multiple-line /* . */ comments is not supported. Short-form commands do work within single-line /*! . */ version comments, as do /*+ . */ optimizer-hint comments, which are stored in object definitions. If there is a concern that optimizer-hint comments may be stored in object definitions so that dump files when reloaded with mysql would result in execution of such commands, either invoke mysql with the –binary-mode option or use a reload client other than mysql.

help [arg], \h [arg], \? [arg], ? [arg] Display a help message listing the available mysql commands. If you provide an argument to the help command, mysql uses it as a search string to access server-side help from the contents of the MySQL Reference Manual. For more information, see the section called “MySQL Client Server-Side Help”.
charset charset_name, \C charset_name Change the default character set and issue a SET NAMES statement. This enables the character set to remain synchronized on the client and server if mysql is run with auto-reconnect enabled (which is not recommended), because the specified character set is used for reconnects.
clear, \c Clear the current input. Use this if you change your mind about executing the statement that you are entering.
connect [db_name [host_name]], \r [db_name [host_name]] Reconnect 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. If the connect command specifies a host name argument, that host takes precedence over any –dns-srv-name option given at mysql startup to specify a DNS SRV record.
delimiter str, \d str Change the string that mysql interprets as the separator between SQL statements. The default is the semicolon character (;). The delimiter string can be specified as an unquoted or quoted argument on the delimiter command line. Quoting can be done with either single quote (‘), double quote (“), or backtick (`) characters. To include a quote within a quoted string, either quote the string with a different quote character or escape the quote with a backslash (\) character. Backslash should be avoided outside of quoted strings because it is the escape character for MySQL. For an unquoted argument, the delimiter 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. mysql interprets instances of the delimiter string as a statement delimiter anywhere it occurs, except within quoted strings. Be careful about defining a delimiter that might occur within other words. For example, if you define the delimiter as X, it is not possible to use the word INDEX in statements. mysql interprets this as INDE followed by the delimiter X. When the delimiter recognized by mysql is set to something other than the default of ;, instances of that character are sent to the server without interpretation. However, the server itself still interprets ; as a statement delimiter and processes statements accordingly. This behavior on the server side comes into play for multiple-statement execution (see Multiple Statement Execution Support [3] ), and for parsing the body of stored procedures and functions, triggers, and events (see Section 25.1, “Defining Stored Programs”).
edit, \e Edit the current input statement. mysql checks the values of the EDITOR and VISUAL environment variables to determine which editor to use. The default editor is vi if neither variable is set. The edit command works only in Unix.
ego, \G Send the current statement to the server to be executed and display the result using vertical format.
exit, \q Exit mysql.
go, \g Send the current statement to the server to be executed.
nopager, \n Disable output paging. See the description for pager. The nopager command works only in Unix.
notee, \t Disable output copying to the tee file. See the description for tee.
nowarning, \w Disable display of warnings after each statement.
pager [command], \P [command] Enable output paging. By using the –pager option when you invoke mysql, it is possible to browse or search query results in interactive mode with Unix programs such as less, more, or any other similar program. If you specify no value for the option, mysql checks the value of the PAGER environment variable and sets the pager to that. Pager functionality works only in interactive mode. Output paging can be enabled interactively with the pager command and disabled with nopager. The command takes an optional argument; if given, the paging program is set to that. With no argument, the pager is set to the pager that was set on the command line, or stdout if no pager was specified. Output paging works only in Unix because it uses the popen() function, which does not exist on Windows. For Windows, the tee option can be used instead to save query output, although it is not as convenient as pager for browsing output in some situations.
print, \p Print the current input statement without executing it.
prompt [str], \R [str] Reconfigure the mysql prompt to the given string. The special character sequences that can be used in the prompt are described later in this section. If you specify the prompt command with no argument, mysql resets the prompt to the default of mysql>.
query_attributes name value [name value . ] Define query attributes that apply to the next query sent to the server. For discussion of the purpose and use of query attributes, see Section 9.6, “Query Attributes”. The query_attributes command follows these rules:
- The format and quoting rules for attribute names and values are the same as for the delimiter command.
- The command permits up to 32 attribute name/value pairs. Names and values may be up to 1024 characters long. If a name is given without a value, an error occurs.
- If multiple query_attributes commands are issued prior to query execution, only the last command applies. After sending the query, mysql clears the attribute set.
- If multiple attributes are defined with the same name, attempts to retrieve the attribute value have an undefined result.
- An attribute defined with an empty name cannot be retrieved by name.
- If a reconnect occurs while mysql executes the query, mysql restores the attributes after reconnecting so the query can be executed again with the same attributes.
```
mysql> SELECT LAST_INSERT_ID(3); +-------------------+ | LAST_INSERT_ID(3) | +-------------------+ | 3 | +-------------------+ mysql> SELECT LAST_INSERT_ID(); +------------------+ | LAST_INSERT_ID() | +------------------+ | 3 | +------------------+ mysql> resetconnection; mysql> SELECT LAST_INSERT_ID(); +------------------+ | LAST_INSERT_ID() | +------------------+ | 0 | +------------------+
```
Here are a few tips about the pager command:
```
mysql> pager cat > /tmp/log.txt
```
You can also pass any options for the program that you want to use as your pager:
```
mysql> pager less -n -i -S
```
```
man less
```
```
mysql> pager less -n -i -S -F -X
```
```
mysql> pager cat | tee /dr1/tmp/res.txt \ | tee /dr2/tmp/res2.txt | less -n -i -S
```
You can also combine the tee and pager functions. Have a tee file enabled and pager set to less, and you are able to browse the results using the less program and still have everything appended into a file the same time. The difference between the Unix tee used with the pager command and the mysql built-in tee command is that the built-in tee works even if you do not have the Unix tee available. The built-in tee also logs everything that is printed on the screen, whereas the Unix tee used with pager does not log quite that much. Additionally, tee file logging can be turned on and off interactively from within mysql. This is useful when you want to log some queries to a file, but not others.

The prompt command reconfigures the default mysql> prompt. The string for defining the prompt can contain the following special sequences.

Your full user_name@host_name account name

x, for any “x” not listed above

You can set the prompt in several ways:
```
export MYSQL_PS1="(\u@\h) [\d]> "
```
```
$> mysql --prompt="(\u@\h) [\d]> " (user@host) [database]>
```
```
[mysql] prompt=(\\u@\\h) [\\d]>\\_
```
In this example, note that the backslashes are doubled. If you set the prompt using the prompt option in an option file, it is advisable to double the backslashes when using the special prompt options. There is some overlap in the set of permissible prompt options and the set of special escape sequences that are recognized in option files. (The rules for escape sequences in option files are listed in Section 4.2.2.2, “Using Option Files”.) The overlap may cause you problems if you use single backslashes. For example, \s is interpreted as a space rather than as the current seconds value. The following example shows how to define a prompt within an option file to include the current time in hh:mm:ss> format:
```
[mysql] prompt="\\r:\\m:\\s> "
```
```
mysql> prompt (\u@\h) [\d]>\_ PROMPT set to '(\u@\h) [\d]>\_' (user@host) [database]> (user@host) [database]> prompt Returning to default PROMPT of mysql> mysql>
```
MySQL Client Logging

The mysql client can do these types of logging for statements executed interactively:
- On Unix, mysql writes the statements to a history file. By default, this file is named .mysql_history in your home directory. To specify a different file, set the value of the MYSQL_HISTFILE environment variable.
- On all platforms, if the –syslog option is given, mysql writes the statements to the system logging facility. On Unix, this is syslog; on Windows, it is the Windows Event Log. The destination where logged messages appear is system dependent. On Linux, the destination is often the /var/log/messages file.
The following discussion describes characteristics that apply to all logging types and provides information specific to each logging type.
- How Logging Occurs
- Controlling the History File
- syslog Logging Characteristics
How Logging Occurs

For each enabled logging destination, statement logging occurs as follows:
- Statements are logged only when executed interactively. Statements are noninteractive, for example, when read from a file or a pipe. It is also possible to suppress statement logging by using the –batch or –execute option.
- Statements are ignored and not logged if they match any pattern in the “ignore” list. This list is described later.
- mysql logs each nonignored, nonempty statement line individually.
- If a nonignored statement spans multiple lines (not including the terminating delimiter), mysql concatenates the lines to form the complete statement, maps newlines to spaces, and logs the result, plus a delimiter.
Consequently, an input statement that spans multiple lines can be logged twice. Consider this input:
```
mysql> SELECT -> 'Today is' -> , -> CURDATE() -> ;
```
In this case, mysql logs the “SELECT”, “’Today is’”, “,”, “CURDATE()”, and “;” lines as it reads them. It also logs the complete statement, after mapping SELECT\n’Today is’\n,\nCURDATE() to SELECT ‘Today is’ , CURDATE(), plus a delimiter. Thus, these lines appear in logged output:
```
SELECT 'Today is' , CURDATE() ; SELECT 'Today is' , CURDATE();
```
mysql ignores for logging purposes statements that match any pattern in the “ignore” list. By default, the pattern list is “*IDENTIFIED*:*PASSWORD*”, to ignore statements that refer to passwords. Pattern matching is not case-sensitive. Within patterns, two characters are special:
- ? matches any single character.
- * matches any sequence of zero or more characters.
To specify additional patterns, use the –histignore option or set the MYSQL_HISTIGNORE environment variable. (If both are specified, the option value takes precedence.) The value should be a list of one or more colon-separated patterns, which are appended to the default pattern list.

Patterns specified on the command line might need to be quoted or escaped to prevent your command interpreter from treating them specially. For example, to suppress logging for UPDATE and DELETE statements in addition to statements that refer to passwords, invoke mysql like this:
```
mysql --histignore="*UPDATE*:*DELETE*"
```
Controlling the History File

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. See Section 6.1.2.1, “End-User Guidelines for Password Security”. Statements in the file are accessible from the mysql client when the up-arrow key is used to recall the history. See Disabling Interactive History.

If you do not want to maintain a history file, first remove .mysql_history if it exists. Then use either of the following techniques to prevent it from being created again:
- Set the MYSQL_HISTFILE environment variable to /dev/null. To cause this setting to take effect each time you log in, put it in one of your shell’s startup files.
- Create .mysql_history as a symbolic link to /dev/null; this need be done only once:
```
ln -s /dev/null $HOME/.mysql_history
```
syslog Logging Characteristics

If the –syslog option is given, mysql writes interactive statements to the system logging facility. Message logging has the following characteristics.

Logging occurs at the “information” level. This corresponds to the LOG_INFO priority for syslog on Unix/Linux syslog capability and to EVENTLOG_INFORMATION_TYPE for the Windows Event Log. Consult your system documentation for configuration of your logging capability.

Message size is limited to 1024 bytes.

Messages consist of the identifier MysqlClient followed by these values:
- SYSTEM_USER The operating system user name (login name) or — if the user is unknown.
- MYSQL_USER The MySQL user name (specified with the –user option) or — if the user is unknown.
- CONNECTION_ID: The client connection identifier. This is the same as the CONNECTION_ID() function value within the session.
- DB_SERVER The server host or — if the host is unknown.
- DB The default database or — if no database has been selected.
- QUERY The text of the logged statement.
Here is a sample of output generated on Linux by using –syslog. This output is formatted for readability; each logged message actually takes a single line.
```
Mar 7 12:39:25 myhost MysqlClient[20824]: SYSTEM_USER:'oscar', MYSQL_USER:'my_oscar', CONNECTION_ID:23, DB_SERVER:'127.0.0.1', DB:'--', QUERY:'USE test;' Mar 7 12:39:28 myhost MysqlClient[20824]: SYSTEM_USER:'oscar', MYSQL_USER:'my_oscar', CONNECTION_ID:23, DB_SERVER:'127.0.0.1', DB:'test', QUERY:'SHOW TABLES;'
```
MySQL Client Server-Side Help
```
mysql> help search_string
```
If you provide an argument to the help command, mysql uses it as a search string to access server-side help from the contents of the MySQL Reference Manual. The proper operation of this command requires that the help tables in the mysql database be initialized with help topic information (see Section 5.1.17, “Server-Side Help Support”).

If there is no match for the search string, the search fails:
```
mysql> help me Nothing found Please try to run 'help contents' for a list of all accessible topics
```
Use help contents to see a list of the help categories:
```
mysql> help contents You asked for help about help category: "Contents" For more information, type 'help ', where 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
```
If the search string matches multiple items, mysql shows a list of matching topics:
```
mysql> help logs Many help items for your request exist. To make a more specific request, please type 'help ', where is one of the following topics: SHOW SHOW BINARY LOGS SHOW ENGINE SHOW LOGS
```
Use a topic as the search string to see the help entry for that topic:
```
mysql> help show binary logs Name: 'SHOW BINARY LOGS' Description: Syntax: SHOW BINARY LOGS SHOW MASTER LOGS Lists the binary log files on the server. This statement is used as part of the procedure described in [purge-binary-logs], that shows how to determine which logs can be purged.
```
```
mysql> SHOW BINARY LOGS; +---------------+-----------+-----------+ | Log_name | File_size | Encrypted | +---------------+-----------+-----------+ | binlog.000015 | 724935 | Yes | | binlog.000016 | 733481 | Yes | +---------------+-----------+-----------+
```
The search string can contain the wildcard characters % and _. These have the same meaning as for pattern-matching operations performed with the LIKE operator. For example, HELP rep% returns a list of topics that begin with rep:
```
mysql> HELP rep% Many help items for your request exist. To make a more specific request, please type 'help ', where is one of the following topics: REPAIR TABLE REPEAT FUNCTION REPEAT LOOP REPLACE REPLACE FUNCTION
```
Executing SQL Statements from a Text File

The mysql client typically is used interactively, like this:
```
mysql db_name
```
However, it is also possible to put your SQL statements in a file and then tell mysql to read its input from that file. To do so, create a text file text_file that contains the statements you wish to execute. Then invoke mysql as shown here:
```
mysql db_name < text_file
```
If you place a USE db_name statement as the first statement in the file, it is unnecessary to specify the database name on the command line:
```
mysql < text_file
```
If you are already running mysql, you can execute an SQL script file using the source command or \. command:
```
mysql> source file_name mysql> \. file_name
```
Sometimes you may want your script to display progress information to the user. For this you can insert statements like this:
```
SELECT '' AS ' ';
```
The statement shown outputs .

You can also invoke mysql with the --verbose option, which causes each statement to be displayed before the result that it produces.

mysql 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 mysql to change its default character set. To do that, invoke mysql with an option such as --default-character-set=utf8mb4.

For more information about batch mode, see Section 3.5, “Using mysql in Batch Mode”.

MySQL Client Tips

This section provides information about techniques for more effective use of mysql and about mysql operational behavior.
- Input-Line Editing
- Disabling Interactive History
- Unicode Support on Windows
- Displaying Query Results Vertically
- Using Safe-Updates Mode (--safe-updates)
- Disabling mysql Auto-Reconnect
- mysql Client Parser Versus Server Parser
mysql supports input-line editing, which enables you to modify the current input line in place or recall previous input lines. For example, the left-arrow and right-arrow keys move horizontally within the current input line, and the up-arrow and down-arrow keys move up and down through the set of previously entered lines. Backspace deletes the character before the cursor and typing new characters enters them at the cursor position. To enter the line, press Enter.

On Windows, the editing key sequences are the same as supported for command editing in console windows. On Unix, the key sequences depend on the input library used to build mysql (for example, the libedit or readline library).

Documentation for the libedit and readline libraries is available online. To change the set of key sequences permitted by a given input library, define key bindings in the library startup file. This is a file in your home directory: .editrc for libedit and .inputrc for readline.

For example, in libedit, Control+W deletes everything before the current cursor position and Control+U deletes the entire line. In readline, Control+W deletes the word before the cursor and Control+U deletes everything before the current cursor position. If mysql was built using libedit, a user who prefers the readline behavior for these two keys can put the following lines in the .editrc file (creating the file if necessary):
```
bind "^W" ed-delete-prev-word bind "^U" vi-kill-line-prev
```
To see the current set of key bindings, temporarily put a line that says only bind at the end of .editrc. mysql shows the bindings when it starts. Disabling Interactive History

The up-arrow key enables you to recall input lines from current and previous sessions. In cases where a console is shared, this behavior may be unsuitable. mysql supports disabling the interactive history partially or fully, depending on the host platform.

On Windows, the history is stored in memory. Alt+F7 deletes all input lines stored in memory for the current history buffer. It also deletes the list of sequential numbers in front of the input lines displayed with F7 and recalled (by number) with F9. New input lines entered after you press Alt+F7 repopulate the current history buffer. Clearing the buffer does not prevent logging to the Windows Event Viewer, if the --syslog option was used to start mysql. Closing the console window also clears the current history buffer.

To disable interactive history on Unix, first delete the .mysql_history file, if it exists (previous entries are recalled otherwise). Then start mysql with the --histignore="*" option to ignore all new input lines. To re-enable the recall (and logging) behavior, restart mysql without the option.

If you prevent the .mysql_history file from being created (see Controlling the History File) and use --histignore="*" to start the mysql client, the interactive history recall facility is disabled fully. Alternatively, if you omit the --histignore option, you can recall the input lines entered during the current session. Unicode Support on Windows

Windows provides APIs based on UTF-16LE for reading from and writing to the console; the mysql client for Windows is able to use these APIs. The Windows installer creates an item in the MySQL menu named MySQL command line client - Unicode. This item invokes the mysql client with properties set to communicate through the console to the MySQL server using Unicode.

To take advantage of this support manually, run mysql within a console that uses a compatible Unicode font and set the default character set to a Unicode character set that is supported for communication with the server:
1. Open a console window.
2. Go to the console window properties, select the font tab, and choose Lucida Console or some other compatible Unicode font. This is necessary because console windows start by default using a DOS raster font that is inadequate for Unicode.
3. Execute mysql.exe with the --default-character-set=utf8mb4 (or utf8mb3) option. This option is necessary because utf16le is one of the character sets that cannot be used as the client character set. See the section called “Impermissible Client Character Sets”.
With those changes, mysql uses the Windows APIs to communicate with the console using UTF-16LE, and communicate with the server using UTF-8. (The menu item mentioned previously sets the font and character set as just described.)

To avoid those steps each time you run mysql, you can create a shortcut that invokes mysql.exe. The shortcut should set the console font to Lucida Console or some other compatible Unicode font, and pass the --default-character-set=utf8mb4 (or utf8mb3) option to mysql.exe.

Alternatively, create a shortcut that only sets the console font, and set the character set in the [mysql] group of your my.ini file:
```
[mysql] default-character-set=utf8mb4 # or utf8mb3
```
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: Jones reply: jones@example.com mail_to: "John Smith" sbj: UTF-8 txt: >>>>> "John" == John Smith writes: John> Hi. I think this is a good idea. Is anyone familiar John> with UTF-8 or Unicode? Otherwise, I'll put this on my John> TODO list and see what happens. Yes, please do that. Regards, Jones file: inbox-jani-1 hash: 190402944 1 row in set (0.09 sec)
```
Using Safe-Updates Mode (--safe-updates)

For beginners, a useful startup option is --safe-updates (or --i-am-a-dummy, which has the same effect). Safe-updates mode is helpful for cases when you might have issued an UPDATE or DELETE statement but forgotten the WHERE clause indicating which rows to modify. Normally, such statements update or delete all rows in the table. With --safe-updates, you can modify rows only by specifying the key values that identify them, or a LIMIT clause, or both. This helps prevent accidents. Safe-updates mode also restricts SELECT statements that produce (or are estimated to produce) very large result sets.

The --safe-updates option causes mysql to execute the following statement when it connects to the MySQL server, to set the session values of the sql_safe_updates, sql_select_limit, and max_join_size system variables:
```
SET sql_safe_updates=1, sql_select_limit=1000, max_join_size=1000000;
```
The SET statement affects statement processing as follows:
```
UPDATE tbl_name SET not_key_column=val WHERE key_column=val; UPDATE tbl_name SET not_key_column=val LIMIT 1;
```
To specify result set limits different from 1,000 and 1,000,000, you can override the defaults by using the --select-limit and --max-join-size options when you invoke mysql:
```
mysql --safe-updates --select-limit=500 --max-join-size=10000
```
It is possible for UPDATE and DELETE statements to produce an error in safe-updates mode even with a key specified in the WHERE clause, if the optimizer decides not to use the index on the key column:
- Range access on the index cannot be used if memory usage exceeds that permitted by the range_optimizer_max_mem_size system variable. The optimizer then falls back to a table scan. See the section called “Limiting Memory Use for Range Optimization”.
- If key comparisons require type conversion, the index may not be used (see Section 8.3.1, “How MySQL Uses Indexes”). Suppose that an indexed string column c1 is compared to a numeric value using WHERE c1 = 2222. For such comparisons, the string value is converted to a number and the operands are compared numerically (see Section 12.3, “Type Conversion in Expression Evaluation”), preventing use of the index. If safe-updates mode is enabled, an error occurs.
As of MySQL 8.0.13, safe-updates mode also includes these behaviors:
- EXPLAIN with UPDATE and DELETE statements does not produce safe-updates errors. This enables use of EXPLAIN plus SHOW WARNINGS to see why an index is not used, which can be helpful in cases such as when a range_optimizer_max_mem_size violation or type conversion occurs and the optimizer does not use an index even though a key column was specified in the WHERE clause.
- When a safe-updates error occurs, the error message includes the first diagnostic that was produced, to provide information about the reason for failure. For example, the message may indicate that the range_optimizer_max_mem_size value was exceeded or type conversion occurred, either of which can preclude use of an index.
- For multiple-table deletes and updates, an error is produced with safe updates enabled only if any target table uses a table scan.
Disabling mysql Auto-Reconnect

If the mysql client loses its connection to the server while sending a statement, it immediately and automatically tries to reconnect once to the server and send the statement again. However, even if mysql succeeds in reconnecting, your first connection has ended and all your previous session objects and settings are lost: temporary tables, the autocommit mode, and user-defined and session variables. Also, any current transaction rolls back. This behavior may be dangerous for you, as in the following example where the server was shut down and restarted between the first and second statements without you knowing it:
```
mysql> SET @a=1; Query OK, 0 rows affected (0.05 sec) mysql> INSERT INTO t VALUES(@a); ERROR 2006: MySQL server has gone away No connection. Trying to reconnect. Connection id: 1 Current database: test Query OK, 1 row affected (1.30 sec) mysql> SELECT * FROM t; +------+ | a | +------+ | NULL | +------+ 1 row in set (0.05 sec)
```
The @a user variable has been lost with the connection, and after the reconnection it is undefined. If it is important to have mysql terminate with an error if the connection has been lost, you can start the mysql client with the --skip-reconnect option.

For more information about auto-reconnect and its effect on state information when a reconnection occurs, see Automatic Reconnection Control [5] . mysql Client Parser Versus Server Parser

The mysql client uses a parser on the client side that is not a duplicate of the complete parser used by the mysqld server on the server side. This can lead to differences in treatment of certain constructs. Examples:
- The server parser treats strings delimited by " characters as identifiers rather than as plain strings if the ANSI_QUOTES SQL mode is enabled. The mysql client parser does not take the ANSI_QUOTES SQL mode into account. It treats strings delimited by ", ', and ` characters the same, regardless of whether ANSI_QUOTES is enabled.
- Within /*! . */ and /*+ . */ comments, the mysql client parser interprets short-form mysql commands. The server parser does not interpret them because these commands have no meaning on the server side. If it is desirable for mysql not to interpret short-form commands within comments, a partial workaround is to use the --binary-mode option, which causes all mysql commands to be disabled except \C and \d in noninteractive mode (for input piped to mysql or loaded using the source command).
Copyright

Copyright © 1997, 2023, Oracle and/or its affiliates.

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.

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.

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/.

Notes
1. MySQL Shell 8.0
  https://dev.mysql.com/doc/mysql-shell/8.0/en/
2. C API Basic Data Structures
  https://dev.mysql.com/doc/c-api/8.0/en/c-api-data-structures.html
3. Multiple Statement Execution Support
  https://dev.mysql.com/doc/c-api/8.0/en/c-api-multiple-queries.html
4. mysql_change_user()
  https://dev.mysql.com/doc/c-api/8.0/en/mysql-change-user.html
5. Automatic Reconnection Control
  https://dev.mysql.com/doc/c-api/8.0/en/c-api-auto-reconnect.html
See Also

For more information, please refer to the MySQL Reference Manual, which may already be installed locally and which is also available online at http://dev.mysql.com/doc/.

Author

Referenced By

The man page mariadb(1) is an alias of mysql(1).

MySQL IN operator

In this article, we describes how to use MySQL IN operator to test whether a value is included in a list.

If you want to test whether a value is included in a list, you can use the IN operator.

The IN operator returns 1 if the specified list includes the specified value, otherwise it returns 0 .

MySQL IN syntax

IN is a binary operator, it requires 2 operands. The following is the syntax of the IN operator:
```
expression IN (value1, value2. ) 
```
- expression can be a column name, a value, or an expression (such as function calls, arithmetic operations, etc.).
- (value1, value2. ) is comma-separated list of values to match in the parentheses.
- There is at least one value in (value1, value2. ) .
MySQL IN algorithm

If the operand on the left side of the IN operator is one item of the list on the right, the IN operator returns 1 . Otherwise, it returns 0 .

The IN operator is a simplified version of multiple OR operators. For example, the following IN statement:
```
name IN ('Alice', 'Tim', 'Jack') 
```
Equivalent to the following OR statement:
```
name = 'Alice' OR name = 'Tim' OR name = 'Jack' 
```
The algorithm of the IN operator is as follows:
```
SELECT  1 IN (1, 2),  3 IN (1, 2),  'A' IN ('A', 'B'),  'C' IN ('A', 'B'); 
```
```
+-------------+-------------+-------------------+-------------------+ | 1 IN (1, 2) | 3 IN (1, 2) | 'A' IN ('A', 'B') | 'C' IN ('A', 'B') | +-------------+-------------+-------------------+-------------------+ | 1 | 0 | 1 | 0 | +-------------+-------------+-------------------+-------------------+
```
```
SELECT  NULL IN (1, 2),  NULL IN (1, 2, NULL); 
```
```
+----------------+----------------------+ | NULL IN (1, 2) | NULL IN (1, 2, NULL) | +----------------+----------------------+ | NULL | NULL | +----------------+----------------------+
```
```
SELECT 1 IN (1, NULL), 2 IN (1, NULL); 
```
```
+----------------+----------------+ | 1 IN (1, NULL) | 2 IN (1, NULL) | +----------------+----------------+ | 1 | NULL | +----------------+----------------+
```
MySQL IN examples

In the following example, we use the actor table from Sakila sample database as a demonstration.

The following statement will return all of actors whose last names is ALLEN or DAVIS . The result of this statement is exactly the same as the example in our MySQL OR tutorial.
```
SELECT *  FROM actor  WHERE last_name IN ('ALLEN', 'DAVIS'); 
```
```
+----------+------------+-----------+---------------------+ | actor_id | first_name | last_name | last_update | +----------+------------+-----------+---------------------+ | 118 | CUBA | ALLEN | 2006-02-15 04:34:33 | | 145 | KIM | ALLEN | 2006-02-15 04:34:33 | | 194 | MERYL | ALLEN | 2006-02-15 04:34:33 | | 4 | JENNIFER | DAVIS | 2006-02-15 04:34:33 | | 101 | SUSAN | DAVIS | 2006-02-15 04:34:33 | | 110 | SUSAN | DAVIS | 2006-02-15 04:34:33 | +----------+------------+-----------+---------------------+
```
Conclusion

In this article, we leared how to use MySQL IN operator to test whether a value is included in a list. The main points of the IN operator are as follows:
- IN is a binary operator and requires 2 operands.
- The left operand of IN operator is a column name or value, and the right operand is the value list or the result of a subquery.
- When the operand on the left side of the IN operator is included in the lists on the right side, the IN operator returns 1 . Otherwise, it returns 0 .
- A combination of multiple OR can be replaced by IN .
- The negation operation of the IN operator is NOT IN .
Related posts:

MySQL IN operator

mysql – Man Page

MySQL Client Options

MySQL Client Commands

MySQL Client Logging

MySQL Client Server-Side Help

Executing SQL Statements from a Text File

MySQL Client Tips

Copyright

Notes

See Also

Author

Referenced By

MySQL IN operator

MySQL IN syntax

MySQL IN algorithm

MySQL IN examples

Conclusion

Related posts: