13.7.1.4 GRANT Statement

GRANT
    priv_type [(column_list)]
      [, priv_type [(column_list)]] ...
    ON [object_type] priv_level
    TO user [auth_option] [, user [auth_option]] ...
    [REQUIRE {NONE | tls_option [[AND] tls_option] ...}]
    [WITH {GRANT OPTION | resource_option} ...]

GRANT PROXY ON user
    TO user [, user] ...
    [WITH GRANT OPTION]

object_type: {
    TABLE
  | FUNCTION
  | PROCEDURE
}

priv_level: {
    *
  | *.*
  | db_name.*
  | db_name.tbl_name
  | tbl_name
  | db_name.routine_name
}

user:
    (see Section 6.2.4, “Specifying Account Names”)

auth_option: {
    IDENTIFIED BY 'auth_string'
  | IDENTIFIED WITH auth_plugin
  | IDENTIFIED WITH auth_plugin BY 'auth_string'
  | IDENTIFIED WITH auth_plugin AS 'auth_string'
  | IDENTIFIED BY PASSWORD 'auth_string'
}

tls_option: {
    SSL
  | X509
  | CIPHER 'cipher'
  | ISSUER 'issuer'
  | SUBJECT 'subject'
}

resource_option: {
  | MAX_QUERIES_PER_HOUR count
  | MAX_UPDATES_PER_HOUR count
  | MAX_CONNECTIONS_PER_HOUR count
  | MAX_USER_CONNECTIONS count
}

The GRANT statement grants privileges to MySQL user accounts. There are several aspects to the GRANT statement, described under the following topics:

GRANT General Overview

The GRANT statement grants privileges to MySQL user accounts.

To grant a privilege with GRANT, you must have the GRANT OPTION privilege, and you must have the privileges that you are granting. (Alternatively, if you have the UPDATE privilege for the grant tables in the mysql system database, you can grant any account any privilege.) When the read_only system variable is enabled, GRANT additionally requires the SUPER privilege.

The REVOKE statement is related to GRANT and enables administrators to remove account privileges. See Section 13.7.1.6, “REVOKE Statement”.

Each account name uses the format described in Section 6.2.4, “Specifying Account Names”. For example:

GRANT ALL ON db1.* TO 'jeffrey'@'localhost';

The host name part of the account, if omitted, defaults to '%'.

Normally, a database administrator first uses CREATE USER to create an account and define its nonprivilege characteristics such as its password, whether it uses secure connections, and limits on access to server resources, then uses GRANT to define its privileges. ALTER USER may be used to change the nonprivilege characteristics of existing accounts. For example:

CREATE USER 'jeffrey'@'localhost' IDENTIFIED BY 'password';
GRANT ALL ON db1.* TO 'jeffrey'@'localhost';
GRANT SELECT ON db2.invoice TO 'jeffrey'@'localhost';
ALTER USER 'jeffrey'@'localhost' WITH MAX_QUERIES_PER_HOUR 90;
Note

Examples shown here include no IDENTIFIED clause. It is assumed that you establish passwords with CREATE USER at account-creation time to avoid creating insecure accounts.

Note

If an account named in a GRANT statement does not already exist, GRANT may create it under the conditions described later in the discussion of the NO_AUTO_CREATE_USER SQL mode. It is also possible to use GRANT to specify nonprivilege account characteristics such as whether it uses secure connections and limits on access to server resources.

However, use of GRANT to create accounts or define nonprivilege characteristics is deprecated as of MySQL 5.7.6. Instead, perform these tasks using CREATE USER or ALTER USER.

From the mysql program, GRANT responds with Query OK, 0 rows affected when executed successfully. To determine what privileges result from the operation, use SHOW GRANTS. See Section 13.7.5.21, “SHOW GRANTS Statement”.

Important

Under some circumstances, GRANT may be recorded in server logs or on the client side in a history file such as ~/.mysql_history, which means that cleartext passwords may be read by anyone having read access to that information. For information about the conditions under which this occurs for the server logs and how to control it, see Section 6.1.2.3, “Passwords and Logging”. For similar information about client-side logging, see Section 4.5.1.3, “mysql Client Logging”.

GRANT supports host names up to 60 characters long. User names can be up to 32 characters. Database, table, column, and routine names can be up to 64 characters.

Warning

Do not attempt to change the permissible length for user names by altering the mysql.user system table. Doing so results in unpredictable behavior which may even make it impossible for users to log in to the MySQL server. Never alter the structure of tables in the mysql system database in any manner except by means of the procedure described in Section 2.11, “Upgrading MySQL”.

Object Quoting Guidelines

Several objects within GRANT statements are subject to quoting, although quoting is optional in many cases: Account, database, table, column, and routine names. For example, if a user_name or host_name value in an account name is legal as an unquoted identifier, you need not quote it. However, quotation marks are necessary to specify a user_name string containing special characters (such as -), or a host_name string containing special characters or wildcard characters such as % (for example, 'test-user'@'%.com'). Quote the user name and host name separately.

To specify quoted values:

  • Quote database, table, column, and routine names as identifiers.

  • Quote user names and host names as identifiers or as strings.

  • Quote passwords as strings.

For string-quoting and identifier-quoting guidelines, see Section 9.1.1, “String Literals”, and Section 9.2, “Schema Object Names”.

The _ and % wildcards are permitted when specifying database names in GRANT statements that grant privileges at the database level (GRANT ... ON db_name.*). This means, for example, that to use a _ character as part of a database name, specify it as \_ in the GRANT statement, to prevent the user from being able to access additional databases matching the wildcard pattern (for example, GRANT ... ON `foo\_bar`.* TO ...).

When a database name not is used to grant privileges at the database level, but as a qualifier for granting privileges to some other object such as a table or routine (for example, GRANT ... ON db_name.tbl_name), wildcard characters are treated as normal characters.

Privileges Supported by MySQL

The following table summarizes the permissible priv_type privilege types that can be specified for the GRANT and REVOKE statements, and the levels at which each privilege can be granted. For additional information about each privilege, see Section 6.2.2, “Privileges Provided by MySQL”.

Table 13.8 Permissible Privileges for GRANT and REVOKE

Privilege Meaning and Grantable Levels
ALL [PRIVILEGES] Grant all privileges at specified access level except GRANT OPTION and PROXY.
ALTER Enable use of ALTER TABLE. Levels: Global, database, table.
ALTER ROUTINE Enable stored routines to be altered or dropped. Levels: Global, database, routine.
CREATE Enable database and table creation. Levels: Global, database, table.
CREATE ROUTINE Enable stored routine creation. Levels: Global, database.
CREATE TABLESPACE Enable tablespaces and log file groups to be created, altered, or dropped. Level: Global.
CREATE TEMPORARY TABLES Enable use of CREATE TEMPORARY TABLE. Levels: Global, database.
CREATE USER Enable use of CREATE USER, DROP USER, RENAME USER, and REVOKE ALL PRIVILEGES. Level: Global.
CREATE VIEW Enable views to be created or altered. Levels: Global, database, table.
DELETE Enable use of DELETE. Level: Global, database, table.
DROP Enable databases, tables, and views to be dropped. Levels: Global, database, table.
EVENT Enable use of events for the Event Scheduler. Levels: Global, database.
EXECUTE Enable the user to execute stored routines. Levels: Global, database, routine.
FILE Enable the user to cause the server to read or write files. Level: Global.
GRANT OPTION Enable privileges to be granted to or removed from other accounts. Levels: Global, database, table, routine, proxy.
INDEX Enable indexes to be created or dropped. Levels: Global, database, table.
INSERT Enable use of INSERT. Levels: Global, database, table, column.
LOCK TABLES Enable use of LOCK TABLES on tables for which you have the SELECT privilege. Levels: Global, database.
PROCESS Enable the user to see all processes with SHOW PROCESSLIST. Level: Global.
PROXY Enable user proxying. Level: From user to user.
REFERENCES Enable foreign key creation. Levels: Global, database, table, column.
RELOAD Enable use of FLUSH operations. Level: Global.
REPLICATION CLIENT Enable the user to ask where source or replica servers are. Level: Global.
REPLICATION SLAVE Enable replicas to read binary log events from the source. Level: Global.
SELECT Enable use of SELECT. Levels: Global, database, table, column.
SHOW DATABASES Enable SHOW DATABASES to show all databases. Level: Global.
SHOW VIEW Enable use of SHOW CREATE VIEW. Levels: Global, database, table.
SHUTDOWN Enable use of mysqladmin shutdown. Level: Global.
SUPER Enable use of other administrative operations such as CHANGE MASTER TO, KILL, PURGE BINARY LOGS, SET GLOBAL, and mysqladmin debug command. Level: Global.
TRIGGER Enable trigger operations. Levels: Global, database, table.
UPDATE Enable use of UPDATE. Levels: Global, database, table, column.
USAGE Synonym for no privileges

A trigger is associated with a table. To create or drop a trigger, you must have the TRIGGER privilege for the table, not the trigger.

In GRANT statements, the ALL [PRIVILEGES] or PROXY privilege must be named by itself and cannot be specified along with other privileges. ALL [PRIVILEGES] stands for all privileges available for the level at which privileges are to be granted except for the GRANT OPTION and PROXY privileges.

USAGE can be specified to create a user that has no privileges, or to specify the REQUIRE or WITH clauses for an account without changing its existing privileges. (However, use of GRANT to define nonprivilege characteristics is deprecated.

MySQL account information is stored in the tables of the mysql system database. For additional details, consult Section 6.2, “Access Control and Account Management”, which discusses the mysql system database and the access control system extensively.

If the grant tables hold privilege rows that contain mixed-case database or table names and the lower_case_table_names system variable is set to a nonzero value, REVOKE cannot be used to revoke these privileges. It will be necessary to manipulate the grant tables directly. (GRANT will not create such rows when lower_case_table_names is set, but such rows might have been created prior to setting that variable.)

Privileges can be granted at several levels, depending on the syntax used for the ON clause. For REVOKE, the same ON syntax specifies which privileges to remove.

For the global, database, table, and routine levels, GRANT ALL assigns only the privileges that exist at the level you are granting. For example, GRANT ALL ON db_name.* is a database-level statement, so it does not grant any global-only privileges such as FILE. Granting ALL does not assign the GRANT OPTION or PROXY privilege.

The object_type clause, if present, should be specified as TABLE, FUNCTION, or PROCEDURE when the following object is a table, a stored function, or a stored procedure.

The privileges that a user holds for a database, table, column, or routine are formed additively as the logical OR of the account privileges at each of the privilege levels, including the global level. It is not possible to deny a privilege granted at a higher level by absence of that privilege at a lower level. For example, this statement grants the SELECT and INSERT privileges globally:

GRANT SELECT, INSERT ON *.* TO u1;

The globally granted privileges apply to all databases, tables, and columns, even though not granted at any of those lower levels.

Details of the privilege-checking procedure are presented in Section 6.2.6, “Access Control, Stage 2: Request Verification”.

If you are using table, column, or routine privileges for even one user, the server examines table, column, and routine privileges for all users and this slows down MySQL a bit. Similarly, if you limit the number of queries, updates, or connections for any users, the server must monitor these values.

MySQL enables you to grant privileges on databases or tables that do not exist. For tables, the privileges to be granted must include the CREATE privilege. This behavior is by design, and is intended to enable the database administrator to prepare user accounts and privileges for databases or tables that are to be created at a later time.

Important

MySQL does not automatically revoke any privileges when you drop a database or table. However, if you drop a routine, any routine-level privileges granted for that routine are revoked.

Account Names and Passwords

A user value in a GRANT statement indicates a MySQL account to which the statement applies. To accommodate granting rights to users from arbitrary hosts, MySQL supports specifying the user value in the form 'user_name'@'host_name'.

You can specify wildcards in the host name. For example, 'user_name'@'%.example.com' applies to user_name for any host in the example.com domain, and 'user_name'@'198.51.100.%' applies to user_name for any host in the 198.51.100 class C subnet.

The simple form 'user_name' is a synonym for 'user_name'@'%'.

MySQL does not support wildcards in user names. To refer to an anonymous user, specify an account with an empty user name with the GRANT statement:

GRANT ALL ON test.* TO ''@'localhost' ...;

In this case, any user who connects from the local host with the correct password for the anonymous user will be permitted access, with the privileges associated with the anonymous-user account.

For additional information about user name and host name values in account names, see Section 6.2.4, “Specifying Account Names”.

Warning

If you permit local anonymous users to connect to the MySQL server, you should also grant privileges to all local users as 'user_name'@'localhost'. Otherwise, the anonymous user account for localhost in the mysql.user system table is used when named users try to log in to the MySQL server from the local machine. For details, see Section 6.2.5, “Access Control, Stage 1: Connection Verification”.

To determine whether this issue applies to you, execute the following query, which lists any anonymous users:

SELECT Host, User FROM mysql.user WHERE User='';

To avoid the problem just described, delete the local anonymous user account using this statement:

DROP USER ''@'localhost';

For GRANT syntax that permits an auth_option value to follow a user value, auth_option begins with IDENTIFIED and indicates how the account authenticates by specifying an account authentication plugin, credentials (for example, a password), or both. Syntax of the auth_option clause is the same as for the CREATE USER statement. For details, see Section 13.7.1.2, “CREATE USER Statement”.

Note

Use of GRANT to define account authentication characteristics is deprecated as of MySQL 5.7.6. Instead, establish or change authentication characteristics using CREATE USER or ALTER USER. This GRANT capability will be removed in a future MySQL release.

When IDENTIFIED is present and you have the global grant privilege (GRANT OPTION), any password specified becomes the new password for the account, even if the account exists and already has a password. Without IDENTIFIED, the account password remains unchanged.

Global Privileges

Global privileges are administrative or apply to all databases on a given server. To assign global privileges, use ON *.* syntax:

GRANT ALL ON *.* TO 'someuser'@'somehost';
GRANT SELECT, INSERT ON *.* TO 'someuser'@'somehost';

The CREATE TABLESPACE, CREATE USER, FILE, PROCESS, RELOAD, REPLICATION CLIENT, REPLICATION SLAVE, SHOW DATABASES, SHUTDOWN, and SUPER privileges are administrative and can only be granted globally.

Other privileges can be granted globally or at more specific levels.

GRANT OPTION granted at the global level for any global privilege applies to all global privileges.

MySQL stores global privileges in the mysql.user system table.

Database Privileges

Database privileges apply to all objects in a given database. To assign database-level privileges, use ON db_name.* syntax:

GRANT ALL ON mydb.* TO 'someuser'@'somehost';
GRANT SELECT, INSERT ON mydb.* TO 'someuser'@'somehost';

If you use ON * syntax (rather than ON *.*), privileges are assigned at the database level for the default database. An error occurs if there is no default database.

The CREATE, DROP, EVENT, GRANT OPTION, LOCK TABLES, and REFERENCES privileges can be specified at the database level. Table or routine privileges also can be specified at the database level, in which case they apply to all tables or routines in the database.

MySQL stores database privileges in the mysql.db system table.

Table Privileges

Table privileges apply to all columns in a given table. To assign table-level privileges, use ON db_name.tbl_name syntax:

GRANT ALL ON mydb.mytbl TO 'someuser'@'somehost';
GRANT SELECT, INSERT ON mydb.mytbl TO 'someuser'@'somehost';

If you specify tbl_name rather than db_name.tbl_name, the statement applies to tbl_name in the default database. An error occurs if there is no default database.

The permissible priv_type values at the table level are ALTER, CREATE VIEW, CREATE, DELETE, DROP, GRANT OPTION, INDEX, INSERT, REFERENCES, SELECT, SHOW VIEW, TRIGGER, and UPDATE.

Table-level privileges apply to base tables and views. They do not apply to tables created with CREATE TEMPORARY TABLE, even if the table names match. For information about TEMPORARY table privileges, see Section 13.1.18.2, “CREATE TEMPORARY TABLE Statement”.

MySQL stores table privileges in the mysql.tables_priv system table.

Column Privileges

Column privileges apply to single columns in a given table. Each privilege to be granted at the column level must be followed by the column or columns, enclosed within parentheses.

GRANT SELECT (col1), INSERT (col1, col2) ON mydb.mytbl TO 'someuser'@'somehost';

The permissible priv_type values for a column (that is, when you use a column_list clause) are INSERT, REFERENCES, SELECT, and UPDATE.

MySQL stores column privileges in the mysql.columns_priv system table.

Stored Routine Privileges

The ALTER ROUTINE, CREATE ROUTINE, EXECUTE, and GRANT OPTION privileges apply to stored routines (procedures and functions). They can be granted at the global and database levels. Except for CREATE ROUTINE, these privileges can be granted at the routine level for individual routines.

GRANT CREATE ROUTINE ON mydb.* TO 'someuser'@'somehost';
GRANT EXECUTE ON PROCEDURE mydb.myproc TO 'someuser'@'somehost';

The permissible priv_type values at the routine level are ALTER ROUTINE, EXECUTE, and GRANT OPTION. CREATE ROUTINE is not a routine-level privilege because you must have the privilege at the global or database level to create a routine in the first place.

MySQL stores routine-level privileges in the mysql.procs_priv system table.

Proxy User Privileges

The PROXY privilege enables one user to be a proxy for another. The proxy user impersonates or takes the identity of the proxied user; that is, it assumes the privileges of the proxied user.

GRANT PROXY ON 'localuser'@'localhost' TO 'externaluser'@'somehost';

When PROXY is granted, it must be the only privilege named in the GRANT statement, the REQUIRE clause cannot be given, and the only permitted WITH option is WITH GRANT OPTION.

Proxying requires that the proxy user authenticate through a plugin that returns the name of the proxied user to the server when the proxy user connects, and that the proxy user have the PROXY privilege for the proxied user. For details and examples, see Section 6.2.14, “Proxy Users”.

MySQL stores proxy privileges in the mysql.proxies_priv system table.

Implicit Account Creation

If an account named in a GRANT statement does not exist, the action taken depends on the NO_AUTO_CREATE_USER SQL mode:

  • If NO_AUTO_CREATE_USER is not enabled, GRANT creates the account. This is very insecure unless you specify a nonempty password using IDENTIFIED BY.

  • If NO_AUTO_CREATE_USER is enabled, GRANT fails and does not create the account, unless you specify a nonempty password using IDENTIFIED BY or name an authentication plugin using IDENTIFIED WITH.

If the account already exists, IDENTIFIED WITH is prohibited because it is intended only for use when creating new accounts.

Other Account Characteristics

MySQL can check X.509 certificate attributes in addition to the usual authentication that is based on the user name and credentials. For background information on the use of SSL with MySQL, see Section 6.3, “Using Encrypted Connections”.

The optional REQUIRE clause specifies SSL-related options for a MySQL account. The syntax is the same as for the CREATE USER statement. For details, see Section 13.7.1.2, “CREATE USER Statement”.

Note

Use of GRANT to define account SSL characteristics is deprecated as of MySQL 5.7.6. Instead, establish or change SSL characteristics using CREATE USER or ALTER USER. This GRANT capability will be removed in a future MySQL release.

The optional WITH clause is used for these purposes:

  • To enable a user to grant privileges to other users

  • To specify resource limits for a user

The WITH GRANT OPTION clause gives the user the ability to give to other users any privileges the user has at the specified privilege level.

To grant the GRANT OPTION privilege to an account without otherwise changing its privileges, do this:

GRANT USAGE ON *.* TO 'someuser'@'somehost' WITH GRANT OPTION;

Be careful to whom you give the GRANT OPTION privilege because two users with different privileges may be able to combine privileges!

You cannot grant another user a privilege which you yourself do not have; the GRANT OPTION privilege enables you to assign only those privileges which you yourself possess.

Be aware that when you grant a user the GRANT OPTION privilege at a particular privilege level, any privileges the user possesses (or may be given in the future) at that level can also be granted by that user to other users. Suppose that you grant a user the INSERT privilege on a database. If you then grant the SELECT privilege on the database and specify WITH GRANT OPTION, that user can give to other users not only the SELECT privilege, but also INSERT. If you then grant the UPDATE privilege to the user on the database, the user can grant INSERT, SELECT, and UPDATE.

For a nonadministrative user, you should not grant the ALTER privilege globally or for the mysql system database. If you do that, the user can try to subvert the privilege system by renaming tables!

For additional information about security risks associated with particular privileges, see Section 6.2.2, “Privileges Provided by MySQL”.

It is possible to place limits on use of server resources by an account, as discussed in Section 6.2.16, “Setting Account Resource Limits”. To do so, use a WITH clause that specifies one or more resource_option values. Limits not specified retain their current values. The syntax is the same as for the CREATE USER statement. For details, see Section 13.7.1.2, “CREATE USER Statement”.

Note

Use of GRANT to define account resource limits is deprecated as of MySQL 5.7.6. Instead, establish or change resource limits using CREATE USER or ALTER USER. This GRANT capability will be removed in a future MySQL release.

MySQL and Standard SQL Versions of GRANT

The biggest differences between the MySQL and standard SQL versions of GRANT are:

  • MySQL associates privileges with the combination of a host name and user name and not with only a user name.

  • Standard SQL does not have global or database-level privileges, nor does it support all the privilege types that MySQL supports.

  • MySQL does not support the standard SQL UNDER privilege.

  • Standard SQL privileges are structured in a hierarchical manner. If you remove a user, all privileges the user has been granted are revoked. This is also true in MySQL if you use DROP USER. See Section 13.7.1.3, “DROP USER Statement”.

  • In standard SQL, when you drop a table, all privileges for the table are revoked. In standard SQL, when you revoke a privilege, all privileges that were granted based on that privilege are also revoked. In MySQL, privileges can be dropped with DROP USER or REVOKE statements.

  • In MySQL, it is possible to have the INSERT privilege for only some of the columns in a table. In this case, you can still execute INSERT statements on the table, provided that you insert values only for those columns for which you have the INSERT privilege. The omitted columns are set to their implicit default values if strict SQL mode is not enabled. In strict mode, the statement is rejected if any of the omitted columns have no default value. (Standard SQL requires you to have the INSERT privilege on all columns.) For information about strict SQL mode and implicit default values, see Section 5.1.10, “Server SQL Modes”, and Section 11.6, “Data Type Default Values”.