MySQL 9.5 Reference Manual Including MySQL NDB Cluster 9.5
      This is the Reference Manual for the MySQL Database System,
      version 9.5, through release 9.5.0.
      Differences between minor versions of MySQL 9.5 are
      noted in the present text with reference to release numbers
      (9.5.x). For license
      information, see the Legal
      Notices.
    
This manual is not intended for use with older versions of the MySQL software due to the many functional and other differences between MySQL 9.5 and previous versions. If you are using an earlier release of the MySQL software, please refer to the appropriate manual. For example, the MySQL 8.0 Reference Manual covers the 8.0 bugfix series of MySQL software releases.
Because this manual serves as a reference, it does not provide general instruction on SQL or relational database concepts. It also does not teach you how to use your operating system or command-line interpreter.
The MySQL Database Software is under constant development, and the Reference Manual is updated frequently as well. The most recent version of the manual is available online in searchable form at https://dev.mysql.com/doc/. Other formats also are available there, including downloadable HTML and PDF versions.
The source code for MySQL itself contains internal documentation written using Doxygen. The generated Doxygen content is available from https://dev.mysql.com/doc/index-other.html. It is also possible to generate this content locally from a MySQL source distribution using the instructions at Section 2.8.10, “Generating MySQL Doxygen Documentation Content”.
If you have questions about using MySQL, join the MySQL Community Slack. If you have suggestions concerning additions or corrections to the manual itself, please send them to the http://www.mysql.com/company/contact/.
This manual uses certain typographical conventions:
        Text in this style is used for SQL
        statements; database, table, and column names; program listings
        and source code; and environment variables. Example: “To
        reload the grant tables, use the FLUSH
        PRIVILEGES statement.”
      
        Text in this style indicates input that
        you type in examples.
      
Text in this style indicates the names of executable programs and scripts, examples being mysql (the MySQL command-line client program) and mysqld (the MySQL server executable).
        Text in this style is used for
        variable input for which you should substitute a value of your
        own choosing.
      
Text in this style is used for emphasis.
Text in this style is used in table headings and to convey especially strong emphasis.
        Text in this style is used to indicate a
        program option that affects how the program is executed, or that
        supplies information that is needed for the program to function
        in a certain way. Example: “The
        --host option (short form -h)
        tells the mysql client program the hostname
        or IP address of the MySQL server that it should connect
        to”.
      
        File names and directory names are written like this: “The
        global my.cnf file is located in the
        /etc directory.”
      
        Character sequences are written like this: “To specify a
        wildcard, use the ‘%’
        character.”
      
When commands or statements are prefixed by a prompt, we use these:
$>type a command here#>type a command asC:\>rootheretype a command here(Windows only) mysql>type a mysql statement here
    Commands are issued in your command interpreter. On Unix, this is
    typically a program such as sh,
    csh, or bash. On Windows, the
    equivalent program is command.com or
    cmd.exe, typically run in a console window.
    Statements prefixed by mysql are issued in the
    mysql command-line client.
  
When you enter a command or statement shown in an example, do not type the prompt shown in the example.
    In some areas different systems may be distinguished from each other
    to show that commands should be executed in two different
    environments. For example, while working with replication the
    commands might be prefixed with source and
    replica:
  
source>type a mysql statement on the replication source herereplica>type a mysql statement on the replica here
    Database, table, and column names must often be substituted into
    statements. To indicate that such substitution is necessary, this
    manual uses db_name,
    tbl_name, and
    col_name. For example, you might see a
    statement like this:
  
mysql> SELECT col_name FROM db_name.tbl_name;
This means that if you were to enter a similar statement, you would supply your own database, table, and column names, perhaps like this:
mysql> SELECT author_name FROM biblio_db.author_list;
SQL keywords are not case-sensitive and may be written in any lettercase. This manual uses uppercase.
    In syntax descriptions, square brackets
    (“[” and
    “]”) indicate optional words or
    clauses. For example, in the following statement, IF
    EXISTS is optional:
  
DROP TABLE [IF EXISTS] tbl_name
    When a syntax element consists of a number of alternatives, the
    alternatives are separated by vertical bars
    (“|”). When one member from a set of
    choices may be chosen, the alternatives are
    listed within square brackets (“[”
    and “]”):
  
TRIM([[BOTH | LEADING | TRAILING] [remstr] FROM]str)
    When one member from a set of choices must be
    chosen, the alternatives are listed within braces
    (“{” and
    “}”):
  
{DESCRIBE | DESC} tbl_name [col_name | wild]
    An ellipsis (...) indicates the omission of a
    section of a statement, typically to provide a shorter version of
    more complex syntax. For example,
    SELECT ... INTO
    OUTFILE is shorthand for the form of
    SELECT statement that has an
    INTO OUTFILE clause following other parts of the
    statement.
  
    An ellipsis can also indicate that the preceding syntax element of a
    statement may be repeated. In the following example, multiple
    reset_option values may be given, with
    each of those after the first preceded by commas:
  
RESETreset_option[,reset_option] ...
    Commands for setting shell variables are shown using Bourne shell
    syntax. For example, the sequence to set the CC
    environment variable and run the configure
    command looks like this in Bourne shell syntax:
  
$> CC=gcc ./configure
If you are using csh or tcsh, you must issue commands somewhat differently:
$>setenv CC gcc$>./configure
The Reference Manual source files are written in DocBook XML format. The HTML version and other formats are produced automatically, primarily using the DocBook XSL stylesheets. For information about DocBook, see http://docbook.org/
This manual was originally written by David Axmark and Michael “Monty” Widenius. It is maintained by the MySQL Documentation Team, consisting of Edward Gilmore, Sudharsana Gomadam, Kim seong Loh, Garima Sharma, Carlos Ortiz, Daniel So, and Jon Stephens.