DELETE [LOW_PRIORITY] [QUICK] [IGNORE] FROM tbl_name [PARTITION (partition_list)] [WHERE where_condition] [ORDER BY ...] [LIMIT row_count] [RETURNING select_expr [, select_expr ...]]
DELETE [LOW_PRIORITY] [QUICK] [IGNORE] tbl_name[.*] [, tbl_name[.*]] ... FROM table_references [WHERE where_condition]
DELETE [LOW_PRIORITY] [QUICK] [IGNORE] FROM tbl_name[.*] [, tbl_name[.*]] ... USING table_references [WHERE where_condition]
|LOW_PRIORITY||Wait until all SELECT's are done before starting the statement. Used with storage engines that uses table locking (MyISAM, Aria etc). See HIGH_PRIORITY and LOW_PRIORITY clauses for details.|
|QUICK||Signal the storage engine that it should expect that a lot of rows are deleted. The storage engine engine can do things to speed up the DELETE like ignoring merging of data blocks until all rows are deleted from the block (instead of when a block is half full). This speeds up things at the expanse of lost space in data blocks. At least MyISAM and Aria support this feature.|
|IGNORE||Don't stop the query even if a not-critical error occurs (like data overflow). See How IGNORE works for a full description.|
For the single-table syntax, the
DELETE statement deletes rows
from tbl_name and returns a count of the number of deleted rows. This count can
be obtained by calling the ROW_COUNT() function. The
WHERE clause, if given, specifies the conditions that identify
which rows to delete. With no
WHERE clause, all rows are
deleted. If the
ORDER BY clause is specified, the rows are
deleted in the order that is specified. The
places a limit on the number of rows that can be deleted.
For the multiple-table syntax,
DELETE deletes from each
tbl_name the rows that satisfy the conditions. In this case,
ORDER BY and
LIMIT cannot be used. A
DELETE can also reference tables which are located in different databases; see Identifier Qualifiers for the syntax.
where_condition is an expression that evaluates to true for
each row to be deleted. It is specified as described in SELECT.
Currently, you cannot delete from a table and select from the same table in a subquery.
You need the
DELETE privilege on a table to delete rows from
it. You need only the
SELECT privilege for any columns that
are only read, such as those named in the
WHERE clause. See
MariaDB starting with 10.0
As stated, a
DELETE statement with no
clause deletes all rows. A faster way to do this, when you do not need to know
the number of deleted rows, is to use
TRUNCATE TABLE. However,
within a transaction or if you have a lock on the table,
TRUNCATE TABLE cannot be used whereas
TRUNCATE TABLE, and
MariaDB starting with 10.0.5
DELETE ... RETURNING was introduced in MariaDB 10.0.5.
From MariaDB 10.0.5, it is possible to return a resultset of the deleted rows for a single table to the client by using the syntax
DELETE ... RETURNING select_expr [, select_expr2 ...]]
Any of SQL expression that can be calculated from a single row fields is allowed. Subqueries are allowed. The AS keyword is allowed, so it is possible to use aliases.
The use of aggregate functions is not allowed. RETURNING cannot be used in multi-table DELETEs.
How to use the ORDER BY and LIMIT clauses:
DELETE FROM page_hit ORDER BY timestamp LIMIT 1000000;
How to use the RETURNING clause:
DELETE FROM t RETURNING f1; +------+ | f1 | +------+ | 5 | | 50 | | 500 | +------+
The following statement joins two tables: one is only used to satisfy a WHERE condition, but no row is deleted from it; rows from the other table are deleted, instead.
DELETE post FROM blog INNER JOIN post WHERE blog.id = post.blog_id;