DROP TABLE
Syntax
DROP [TEMPORARY] TABLE [IF EXISTS] [/*COMMENT TO SAVE*/] tbl_name [, tbl_name] ... [WAIT n|NOWAIT] [RESTRICT | CASCADE]
Contents
Description
DROP TABLE
removes one or more tables. You must have the DROP
privilege
for each table. All table data and the table definition are removed, as well as triggers associated to the table, so be
careful with this statement! If any of the tables named in the argument list do
not exist, MariaDB returns an error indicating by name which non-existing tables
it was unable to drop, but it also drops all of the tables in the list that do
exist.
Important: When a table is dropped, user privileges on the table are not automatically dropped. See GRANT.
If another thread is using the table in an explicit transaction or an autocommit transaction, then the thread acquires a metadata lock (MDL) on the table. The DROP TABLE
statement will wait in the "Waiting for table metadata lock" thread state until the MDL is released. MDLs are released in the following cases:
- If an MDL is acquired in an explicit transaction, then the MDL will be released when the transaction ends.
- If an MDL is acquired in an autocommit transaction, then the MDL will be released when the statement ends.
- Transactional and non-transactional tables are handled the same.
Note that for a partitioned table, DROP TABLE
permanently removes the table
definition, all of its partitions, and all of the data which was stored in
those partitions. It also removes the partitioning definition (.par) file
associated with the dropped table.
For each referenced table, DROP TABLE
drops a temporary table with that name, if it exists. If it does not exist, and the TEMPORARY
keyword is not used, it drops a non-temporary table with the same name, if it exists. The TEMPORARY
keyword ensures that a non-temporary table will not accidentally be dropped.
Use IF EXISTS
to prevent an error from occurring for tables that do not
exist. A NOTE
is generated for each non-existent table when using
IF EXISTS
. See SHOW WARNINGS.
If a foreign key references this table, the table cannot be dropped. In this case, it is necessary to drop the foreign key first.
RESTRICT
and CASCADE
are allowed to make porting from other database systems easier. In MariaDB, they do nothing.
The comment before the table names (/*COMMENT TO SAVE*/
) is stored in the binary log. That feature can be used by replication tools to send their internal messages.
It is possible to specify table names as db_name
.tab_name
. This is useful to delete tables from multiple databases with one statement. See Identifier Qualifiers for details.
The DROP privilege is required to use DROP TABLE
on non-temporary tables. For temporary tables, no privilege is required, because such tables are only visible for the current session.
Note: DROP TABLE
automatically commits the current active transaction,
unless you use the TEMPORARY
keyword.
MariaDB starting with 10.5.4
From MariaDB 10.5.4, DROP TABLE
reliably deletes table remnants inside a storage engine even if the .frm
file is missing. Before then, a missing .frm
file would result in the statement failing.
WAIT/NOWAIT
Set the lock wait timeout. See WAIT and NOWAIT.
DROP TABLE in replication
DROP TABLE
has the following characteristics in replication:
DROP TABLE IF EXISTS
are always logged.DROP TABLE
withoutIF EXISTS
for tables that don't exist are not written to the binary log.- Dropping of
TEMPORARY
tables are prefixed in the log withTEMPORARY
. These drops are only logged when running statement or mixed mode replication. - One
DROP TABLE
statement can be logged with up to 3 differentDROP
statements:DROP TEMPORARY TABLE list_of_non_transactional_temporary_tables
DROP TEMPORARY TABLE list_of_transactional_temporary_tables
DROP TABLE list_of_normal_tables
DROP TABLE
on the primary is treated on the replica as DROP TABLE IF EXISTS
. You can change that by setting slave-ddl-exec-mode to STRICT
.
Dropping an Internal #sql-... Table
From MariaDB 10.6, DROP TABLE is atomic and the following does not apply. Until MariaDB 10.5, if the mariadbd process is killed during an ALTER TABLE you may find a table named #sql-... in your data directory. These temporary tables will always be deleted automatically.
If you want to delete one of these tables explicitly you can do so by using the following syntax:
DROP TABLE `#mysql50##sql-...`;
When running an ALTER TABLE…ALGORITHM=INPLACE
that rebuilds the table, InnoDB will create an internal #sql-ib
table.
The same name as the .frm file is used for the intermediate copy of the table. The #sql-ib names are used by TRUNCATE and delayed DROP.
The #sql-ib tables will be deleted automatically.
Dropping All Tables in a Database
The best way to drop all tables in a database is by executing DROP DATABASE, which will drop the database itself, and all tables in it.
However, if you want to drop all tables in the database, but you also want to keep the database itself and any other non-table objects in it, then you would need to execute DROP TABLE
to drop each individual table. You can construct these DROP TABLE
commands by querying the TABLES table in the information_schema database. For example:
SELECT CONCAT('DROP TABLE IF EXISTS `', TABLE_SCHEMA, '`.`', TABLE_NAME, '`;') FROM information_schema.TABLES WHERE TABLE_SCHEMA = 'mydb';
Atomic DROP TABLE
MariaDB starting with 10.6.1
From MariaDB 10.6, DROP TABLE
for a single table is atomic (MDEV-25180) for most engines, including InnoDB, MyRocks, MyISAM and Aria.
This means that if there is a crash (server down or power outage) during DROP TABLE
, all tables
that have been processed so far will be completely dropped, including related trigger files and status entries, and the binary log will include a DROP TABLE
statement for the dropped tables.
Tables for which the drop had not started will be left intact.
In older MariaDB versions, there was a small chance that, during a server crash happening in the middle of DROP TABLE
, some storage engines that were using multiple storage files, like MyISAM, could have only a part of its internal files dropped.
In MariaDB 10.5, DROP TABLE
was extended to be able to delete a table that was only partly dropped (MDEV-11412) as explained above. Atomic DROP TABLE
is the final piece to make DROP TABLE
fully reliable.
Dropping multiple tables is crash-safe.
See Atomic DDL for more information.
Examples
DROP TABLE Employees, Customers;
Notes
Beware that DROP TABLE
can drop both tables and sequences. This is mainly done to allow old tools like mariadb-dump (previously mysqldump) to work with sequences.