• MySQL 5.1 Reference Manual :: 12 SQL Statement Syntax :: 12.4 Database Administration Statements :: 12.4.1 Account Management Statements :: 12.4.1.3 GRANT Syntax
  • 12.4.1.3. GRANT Syntax

    GRANT
        priv_type [(column_list)]
          [, priv_type [(column_list)]] ...
        ON [object_type] priv_level
        TO user [IDENTIFIED BY [PASSWORD] 'password']
            [, user [IDENTIFIED BY [PASSWORD] 'password']] ...
        [REQUIRE {NONE | ssl_option [[AND] ssl_option] ...}]
        [WITH with_option ...]
    
    object_type:
        TABLE
      | FUNCTION
      | PROCEDURE
    
    priv_level:
        *
      | *.*
      | db_name.*
      | db_name.tbl_name
      | tbl_name
      | db_name.routine_name
    
    ssl_option:
        SSL
      | X509
      | CIPHER 'cipher'
      | ISSUER 'issuer'
      | SUBJECT 'subject'
    
    with_option:
        GRANT OPTION
      | MAX_QUERIES_PER_HOUR count
      | MAX_UPDATES_PER_HOUR count
      | MAX_CONNECTIONS_PER_HOUR count
      | MAX_USER_CONNECTIONS count
    

    The GRANT statement enables system administrators to grant privileges to MySQL user accounts. GRANT also serves to specify other account characteristics such as use of secure connections and limits on access to server resources. To use GRANT, you must have the GRANT OPTION privilege, and you must have the privileges that you are granting.

    Normally, CREATE USER is used to create an account and GRANT to define its privileges. However, 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.

    The REVOKE statement is related to GRANT and enables administrators to remove account privileges. To determine what privileges an account has, use SHOW GRANTS. See Section 12.4.1.5, “REVOKE Syntax”, and Section 12.4.5.22, “SHOW GRANTS Syntax”.

    Important

    Some releases of MySQL introduce changes to the structure of the grant tables to add new privileges or features. Whenever you update to a new version of MySQL, you should update your grant tables to make sure that they have the current structure so that you can take advantage of any new capabilities. See Section 4.4.8, “mysql_upgrade — Check Tables for MySQL Upgrade”.

    MySQL Enterprise.  For automated notification of users with inappropriate privileges, subscribe to the MySQL Enterprise Monitor. For more information, see http://www.mysql.com/products/enterprise/advisors.html.

    The following table summarizes the allowable priv_type privilege types that can be specified for the GRANT and REVOKE statements. For additional information about these privileges, see Section 5.4.1, “Privileges Provided by MySQL”.

    Privilege Meaning
    ALL [PRIVILEGES] Grant all privileges at specified access level except GRANT OPTION
    ALTER Enable use of ALTER TABLE
    ALTER ROUTINE Enable stored routines to be altered or dropped
    CREATE Enable database and table creation
    CREATE ROUTINE Enable stored routine creation
    CREATE TEMPORARY TABLES Enable use of CREATE TEMPORARY TABLE
    CREATE USER Enable use of CREATE USER, DROP USER, RENAME USER, and REVOKE ALL PRIVILEGES
    CREATE VIEW Enable views to be created or altered
    DELETE Enable use of DELETE
    DROP Enable databases, tables, and views to be dropped
    EVENT Enable use of events for the Event Scheduler
    EXECUTE Enable the user to execute stored routines
    FILE Enable the user to cause the server to read or write files
    GRANT OPTION Enable privileges to be granted to or removed from other accounts
    INDEX Enable indexes to be created or dropped
    INSERT Enable use of INSERT
    LOCK TABLES Enable use of LOCK TABLES on tables for which you have the SELECT privilege
    PROCESS Enable the user to see all processes with SHOW PROCESSLIST
    REFERENCES Not implemented
    RELOAD Enable use of FLUSH operations
    REPLICATION CLIENT Enable the user to ask where master or slave servers are
    REPLICATION SLAVE Enable replication slaves to read binary log events from the master
    SELECT Enable use of SELECT
    SHOW DATABASES Enable SHOW DATABASES to show all databases
    SHOW VIEW Enable use of SHOW CREATE VIEW
    SHUTDOWN Enable use of mysqladmin shutdown
    SUPER Enable use of other adminstrative operations such as CHANGE MASTER TO, KILL, PURGE BINARY LOGS, SET GLOBAL, and mysqladmin debug command
    TRIGGER Enable triggers to be created or dropped
    UPDATE Enable use of UPDATE
    USAGE Synonym for “no privileges

    The EVENT and TRIGGER privileges were added in MySQL 5.1.6. A trigger is associated with a table, so to create or drop a trigger, you must have the TRIGGER privilege for the table, not the trigger. (Before MySQL 5.1.6, the SUPER privilege was required to create or drop triggers.)

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

    USAGE can be specified when you want to create a user that has no privileges, or to specify the REQUIRE or WITH clauses for an account without changing its existing privileges.

    MySQL account information is stored in the tables of the mysql database. This database and the access control system are discussed extensively in Chapter 5, MySQL Server Administration, which you should consult for additional details.

    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 the 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 take away. The examples shown here include no IDENTIFIED BY 'password' clause for brevity, but you should include one if the account does not already exist to avoid creating an account with no password.

    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';
    

    Before MySQL 5.1.12, privileges also are assigned at the global level if you use ON * syntax and you have not selected a default database. As of 5.1.12, ON * requires a default database and produces an error is there is none.

    The 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.

    Global privileges are stored in the mysql.user 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';
    

    Privileges also are assigned at the database level (for the default database) if you use ON * syntax and you have selected a default database.

    The CREATE, DROP, EVENT, and GRANT OPTION 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.

    Database privileges are stored in the mysql.db and mysql.host tables. GRANT and REVOKE affect the db table, but not the host table, which is rarely used.

    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 allowable priv_type values for a table are ALTER, CREATE VIEW, CREATE, DELETE, DROP, GRANT OPTION, INDEX, INSERT, SELECT, SHOW VIEW, TRIGGER, and UPDATE.

    Table privileges are stored in the mysql.tables_priv 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 allowable priv_type values for a column (that is, when you use a column_list clause) are INSERT, SELECT, and UPDATE.

    Column privileges are stored in the mysql.columns_priv table.

    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 allowable 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 this privilege to create a routine in the first place.

    Routine-level privileges are stored in the mysql.procs_priv table.

    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.

    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 for a database, table, column, or routine are formed additively as the logical OR of the privileges at each of the privilege levels. For example, if a user has a global SELECT privilege, the privilege cannot be denied by an absence of the privilege at the database, table, or column level. Details of the privilege-checking procedure are presented in Section 5.4.5, “Access Control, Stage 2: Request Verification”.

    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.

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

    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@'192.168.1.%' applies to user_name for any host in the 192.168.1 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 allowed access, with the privileges associated with the anonymous-user account.

    For additional information about user and host values in account names, see Section 5.4.3, “Specifying Account Names”.

    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 8.1.1, “Strings”, and Section 8.2, “Schema Object Names”.

    The “_” and “%” wildcards are allowed when specifying database names in GRANT statements that grant privileges at the global or database levels. This means, for example, that if you want to use a “_” character as part of a database name, you should 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 ....

    Warning

    If you allow 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 table (created during MySQL installation) is used when named users try to log in to the MySQL server from the local machine. For details, see Section 5.4.4, “Access Control, Stage 1: Connection Verification”.

    You can determine whether the preceding warning applies to you by executing 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';
    

    GRANT supports host names up to 60 characters long. Database, table, column, and routine names can be up to 64 characters. User names can be up to 16 characters.

    Warning

    The allowable length for user names cannot be changed by altering the mysql.user table. Attempting to do so results in unpredictable behavior which may even make it impossible for users to log in to the MySQL server. You should never alter any of the tables in the mysql database in any manner whatsoever except by means of the procedure described in Section 4.4.8, “mysql_upgrade — Check Tables for MySQL Upgrade”.

    If the NO_AUTO_CREATE_USER SQL mode is not enabled and the account named in a GRANT statement does not exist in the mysql.user table, GRANT creates it. If you specify no IDENTIFIED BY clause or provide an empty password, the user has no password. This is very insecure.

    If NO_AUTO_CREATE_USER is enabled and the account does not exist, GRANT fails and does not create the account unless the IDENTIFIED BY clause is given to provide a nonempty password.

    When the IDENTIFIED BY clause is present and you have global grant privileges, the password becomes the new password for the account, even if the account exists and already has a password.

    MySQL Enterprise.  The MySQL Enterprise Monitor specifically guards against user accounts with no passwords. To find out more, see http://www.mysql.com/products/enterprise/advisors.html.

    REVOKE does not remove mysql.user table entries; you must do that using DROP USER or DELETE.

    Passwords can also be set with the SET PASSWORD statement. See Section 12.4.1.6, “SET PASSWORD Syntax”.

    In the IDENTIFIED BY clause, the password should be given as the literal password value. It is unnecessary to use the PASSWORD() function as it is for the SET PASSWORD statement. For example:

    GRANT ... IDENTIFIED BY 'mypass';
    

    If you do not want to send the password in clear text and you know the hashed value that PASSWORD() would return for the password, you can specify the hashed value preceded by the keyword PASSWORD:

    GRANT ...
    IDENTIFIED BY PASSWORD '*6C8989366EAF75BB670AD8EA7A7FC1176A95CEF4';
    

    The WITH clause is used for several purposes:

    • To enable a user to grant privileges to other users

    • To specify resource limits for a user

    • To specify whether and how a user must use secure connections to the server

    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. You should 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 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 5.4.1, “Privileges Provided by MySQL”.

    Several WITH clause options specify limits on use of server resources by an account:

    • The MAX_QUERIES_PER_HOUR count, MAX_UPDATES_PER_HOUR count, and MAX_CONNECTIONS_PER_HOUR count limits restrict the number of queries, updates, and connections to the server allowed to this account during any given one-hour period. (Queries for which results are served from the query cache do not count against the MAX_QUERIES_PER_HOUR limit.) If count is 0 (the default), this means that there is no limitation for the account.

    • The MAX_USER_CONNECTIONS count limit restricts the maximum number of simultaneous connections to the server by the account. A nonzero count specifies the limit for the account explicitly. If count is 0 (the default), the server determines the number of simultaneous connections for the account from the global value of the max_user_connections system variable. If max_user_connections is also zero, there is no limit for the account.

    To specify resource limits for an existing user without affecting existing privileges, use GRANT USAGE at the global level (ON *.*) and name the limits to be changed. For example:

    GRANT USAGE ON *.* TO ...
      WITH MAX_QUERIES_PER_HOUR 500 MAX_UPDATES_PER_HOUR 100;
    

    Limits not specified retain their current values.

    For more information on restricting access to server resources, see Section 5.5.4, “Setting Account Resource Limits”.

    MySQL can check X509 certificate attributes in addition to the usual authentication that is based on the user name and password. To specify SSL-related options for a MySQL account, use the REQUIRE clause of the GRANT statement. (For background information on the use of SSL with MySQL, see Section 5.5.6, “Using SSL for Secure Connections”.)

    There are a number of different possibilities for limiting connection types for a given account:

    • REQUIRE NONE indicates that the account has no SSL or X509 requirements. This is the default if no SSL-related REQUIRE options are specified. Unencrypted connections are allowed if the user name and password are valid. However, encrypted connections can also be used, at the client's option, if the client has the proper certificate and key files. That is, the client need not specify any SSL command options, in which case the connection will be unencrypted. To use an encrypted connection, the client must specify either the --ssl-ca option, or all three of the --ssl-ca, --ssl-key, and --ssl-cert options.

    • The REQUIRE SSL option tells the server to allow only SSL-encrypted connections for the account.

      GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost'
        IDENTIFIED BY 'goodsecret' REQUIRE SSL;
      

      To connect, the client must specify the --ssl-ca option, and may additionally specify the --ssl-key and --ssl-cert options.

    • REQUIRE X509 means that the client must have a valid certificate but that the exact certificate, issuer, and subject do not matter. The only requirement is that it should be possible to verify its signature with one of the CA certificates.

      GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost'
        IDENTIFIED BY 'goodsecret' REQUIRE X509;
      

      To connect, the client must specify the --ssl-ca, --ssl-key, and --ssl-cert options. This is also true for ISSUER and SUBJECT because those REQUIRE options imply X509.

    • REQUIRE ISSUER 'issuer' places the restriction on connection attempts that the client must present a valid X509 certificate issued by CA 'issuer'. If the client presents a certificate that is valid but has a different issuer, the server rejects the connection. Use of X509 certificates always implies encryption, so the SSL option is unnecessary in this case.

      GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost'
        IDENTIFIED BY 'goodsecret'
        REQUIRE ISSUER '/C=FI/ST=Some-State/L=Helsinki/
          O=MySQL Finland AB/CN=Tonu Samuel/Email=tonu@example.com';
      

      Note that the 'issuer' value should be entered as a single string.

    • REQUIRE SUBJECT 'subject' places the restriction on connection attempts that the client must present a valid X509 certificate containing the subject subject. If the client presents a certificate that is valid but has a different subject, the server rejects the connection.

      GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost'
        IDENTIFIED BY 'goodsecret'
        REQUIRE SUBJECT '/C=EE/ST=Some-State/L=Tallinn/
          O=MySQL demo client certificate/
          CN=Tonu Samuel/Email=tonu@example.com';
      

      Note that the 'subject' value should be entered as a single string.

    • REQUIRE CIPHER 'cipher' is needed to ensure that ciphers and key lengths of sufficient strength are used. SSL itself can be weak if old algorithms using short encryption keys are used. Using this option, you can ask that a specific cipher method is used to allow a connection.

      GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost'
        IDENTIFIED BY 'goodsecret'
        REQUIRE CIPHER 'EDH-RSA-DES-CBC3-SHA';
      

    The SUBJECT, ISSUER, and CIPHER options can be combined in the REQUIRE clause like this:

    GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost'
      IDENTIFIED BY 'goodsecret'
      REQUIRE SUBJECT '/C=EE/ST=Some-State/L=Tallinn/
        O=MySQL demo client certificate/
        CN=Tonu Samuel/Email=tonu@example.com'
      AND ISSUER '/C=FI/ST=Some-State/L=Helsinki/
        O=MySQL Finland AB/CN=Tonu Samuel/Email=tonu@example.com'
      AND CIPHER 'EDH-RSA-DES-CBC3-SHA';
    

    The order of the options does not matter, but no option can be specified twice. The AND keyword is optional between REQUIRE options.

    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.

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

    • In MySQL, privileges are associated 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 12.4.1.2, “DROP USER Syntax”.

    • 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 only with explicit REVOKE statements or by manipulating values stored in the MySQL grant tables.

    • 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 omit those columns for which you do not 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.) Section 5.1.7, “Server SQL Modes”, discusses strict mode. Section 10.1.4, “Data Type Default Values”, discusses implicit default values.