The privileges granted to a MySQL account determine which operations the account can perform. MySQL privileges differ in the contexts in which they apply and at different levels of operation:
Administrative privileges enable users to manage operation of the MySQL server. These privileges are global because they are not specific to a particular database.
Database privileges apply to a database and to all objects within it. These privileges can be granted for specific databases, or globally so that they apply to all databases.
Privileges for database objects such as tables, indexes, views, and stored routines can be granted for specific objects within a database, for all objects of a given type within a database (for example, all tables in a database), or globally for all objects of a given type in all databases).
Information about account privileges is stored in the
tables in the
mysql system database (see
Section 6.2.2, “Grant Tables”). The MySQL server reads the
contents of these tables into memory when it starts and reloads
them under the circumstances indicated in
Section 6.2.6, “When Privilege Changes Take Effect”. Access-control decisions are
based on the in-memory copies of the grant tables.
Some MySQL releases introduce changes to the structure of the grant tables to add new privileges or features. To make sure that you can take advantage of any new capabilities, update your grant tables to have the current structure whenever you upgrade MySQL. See Section 4.4.7, “mysql_upgrade — Check and Upgrade MySQL Tables”.
The following table shows the privilege names used in
REVOKE statements, along with the
column name associated with each privilege in the grant tables and
the context in which the privilege applies.
Table 6.2 Permissible Privileges for GRANT and REVOKE
|Synonym for “all privileges”||Server administration|
|Databases, tables, or indexes|
|Databases, tables, or views|
|File access on server host|
|Databases, tables, or stored routines|
|Tables or columns|
|See ||Server administration|
|Databases or tables|
|Tables or columns|
|Tables or columns|
|Synonym for “no privileges”||Server administration|
The following list provides general descriptions of the privileges available in MySQL. Particular SQL statements might have more specific privilege requirements than indicated here. If so, the description for the statement in question provides the details.
ALL PRIVILEGESprivilege specifier is shorthand. It stands for “all privileges available at a given privilege level” (except
GRANT OPTION). For example, granting
ALLat the global or table level grants all global privileges or all table-level privileges.
ALTERprivilege enables use of the
ALTER TABLEstatement to change the structure of tables.
ALTER TABLEalso requires the
INSERTprivileges. Renaming a table requires
DROPon the old table,
INSERTon the new table.
ALTER ROUTINEprivilege is needed to alter or drop stored routines (procedures and functions).
CREATEprivilege enables creation of new databases and tables.
CREATE ROUTINEprivilege is needed to create stored routines (procedures and functions).
CREATE TABLESPACEprivilege is needed to create, alter, or drop tablespaces and log file groups.
However, other operations on a temporary table, such as
SELECT, require additional privileges for those operations for the database containing the temporary table, or for the nontemporary table of the same name. For more information, see Section 126.96.36.199, “CREATE TEMPORARY TABLE Syntax”.
DELETEprivilege enables rows to be deleted from tables in a database.
DROPprivilege enables you to drop (remove) existing databases, tables, and views. The
DROPprivilege is required in order to use the statement
ALTER TABLE ... DROP PARTITIONon a partitioned table. The
DROPprivilege is also required for
TRUNCATE TABLE. If you grant the
DROPprivilege for the
mysqldatabase to a user, that user can drop the database in which the MySQL access privileges are stored.
EVENTprivilege is required to create, alter, drop, or see events for the Event Scheduler.
EXECUTEprivilege is required to execute stored routines (procedures and functions).
FILEprivilege gives you permission to read and write files on the server host using the
LOAD DATA INFILEand
SELECT ... INTO OUTFILEstatements and the
LOAD_FILE()function. A user who has the
FILEprivilege can read any file on the server host that is either world-readable or readable by the MySQL server. (This implies the user can read any file in any database directory, because the server can access any of those files.) The
FILEprivilege also enables the user to create new files in any directory where the MySQL server has write access. This includes the server's data directory containing the files that implement the privilege tables. As a security measure, the server will not overwrite existing files. As of MySQL 5.5.54, the
FILEprivilege is required to use the
INDEX DIRECTORYtable option for the
GRANT OPTIONprivilege enables you to give to other users or remove from other users those privileges that you yourself possess.
INDEXprivilege enables you to create or drop (remove) indexes.
INDEXapplies to existing tables. If you have the
CREATEprivilege for a table, you can include index definitions in the
LOCK TABLESprivilege enables the use of explicit
LOCK TABLESstatements to lock tables for which you have the
SELECTprivilege. This includes the use of write locks, which prevents other sessions from reading the locked table.
PROCESSprivilege pertains to display of information about the threads executing within the server (that is, information about the statements being executed by sessions). The privilege enables use of
SHOW PROCESSLISTor mysqladmin processlist to see threads belonging to other accounts; you can always see your own threads. The
PROCESSprivilege also enables use of
REFERENCESprivilege is unused before MySQL 5.5.41. As of 5.5.41, creation of a foreign key constraint requires at least one of the
REFERENCESprivileges for the parent table.
RELOADprivilege enables use of the
FLUSHstatement. It also enables mysqladmin commands that are equivalent to
reloadcommand tells the server to reload the grant tables into memory.
flush-privilegesis a synonym for
refreshcommand closes and reopens the log files and flushes all tables. The other
flush-commands perform functions similar to
refresh, but are more specific and may be preferable in some instances. For example, if you want to flush just the log files,
flush-logsis a better choice than
REPLICATION SLAVEprivilege should be granted to accounts that are used by slave servers to connect to the current server as their master. Without this privilege, the slave cannot request updates that have been made to databases on the master server.
SELECTprivilege enables you to select rows from tables in a database.
SELECTstatements require the
SELECTprivilege only if they actually retrieve rows from a table. Some
SELECTstatements do not access tables and can be executed without permission for any database. For example, you can use
SELECTas a simple calculator to evaluate expressions that make no reference to tables:
SELECT 1+1; SELECT PI()*2;
SELECTprivilege is also needed for other statements that read column values. For example,
SELECTis needed for columns referenced on the right hand side of
UPDATEstatements or for columns named in the
SHOW DATABASESprivilege enables the account to see database names by issuing the
SHOW DATABASEstatement. Accounts that do not have this privilege see only databases for which they have some privileges, and cannot use the statement at all if the server was started with the
--skip-show-databaseoption. Note that any global privilege is a privilege for the database.
SUPERprivilege enables these operations and server behaviors:
Enables configuration changes by modifying global system variables. For some system variables, setting the session value also requires the
SUPERprivilege; if so, it is indicated in the variable description. Examples include
Enables starting and stopping replication on slave servers.
Enables use of the
CHANGE MASTER TOstatement.
Enables setting the effective authorization ID when executing a view or stored program. A user with this privilege can specify any account in the
DEFINERattribute of a view or stored program.
Enables use of the mysqladmin debug command.
Enables reading the DES key file by the
Enables control over client connections not permitted to non-
TRIGGERprivilege enables trigger operations. You must have this privilege for a table to create, drop, execute, or display triggers for that table.
When a trigger is activated (by a user who has privileges to execute
DELETEstatements for the table associated with the trigger), trigger execution requires that the user who defined the trigger still have the
UPDATEprivilege enables rows to be updated in tables in a database.
USAGEprivilege specifier stands for “no privileges.” It is used at the global level with
GRANTto modify account attributes such as resource limits or SSL characteristics without naming specific account privileges.
USAGEto indicate that an account has no privileges at a privilege level.
It is a good idea to grant to an account only those privileges
that it needs. You should exercise particular caution in granting
FILE and administrative
FILEprivilege can be abused to read into a database table any files that the MySQL server can read on the server host. This includes all world-readable files and files in the server's data directory. The table can then be accessed using
SELECTto transfer its contents to the client host.
ALTERprivilege may be used to subvert the privilege system by renaming tables.
SHUTDOWNprivilege can be abused to deny service to other users entirely by terminating the server.
PROCESSprivilege can be used to view the plain text of currently executing statements, including statements that set or change passwords.
SUPERprivilege can be used to terminate other sessions or change how the server operates.
Privileges granted for the
mysqldatabase itself can be used to change passwords and other access privilege information. Passwords are stored encrypted, so a malicious user cannot simply read them to know the plain text password. However, a user with write access to the
Passwordcolumn can change an account's password, and then connect to the MySQL server using that account.