DELETE(7) PostgreSQL 9.2.7 Documentation DELETE(7)
DELETE - delete rows of a table
[ WITH [ RECURSIVE ] with_query [, ...] ]
DELETE FROM [ ONLY ] table_name [ * ] [ [ AS ] alias ]
[ USING using_list ]
[ WHERE condition | WHERE CURRENT OF cursor_name ]
[ RETURNING * | output_expression [ [ AS ] output_name ] [, ...] ]
DELETE deletes rows that satisfy the WHERE clause from the specified table. If the WHERE clause is absent, the effect is to delete all rows
in the table. The result is a valid, but empty table.
TRUNCATE(7) is a PostgreSQL extension that provides a faster mechanism to remove all rows from a table.
There are two ways to delete rows in a table using information contained in other tables in the database: using sub-selects, or specifying
additional tables in the USING clause. Which technique is more appropriate depends on the specific circumstances.
The optional RETURNING clause causes DELETE to compute and return value(s) based on each row actually deleted. Any expression using the
table's columns, and/or columns of other tables mentioned in USING, can be computed. The syntax of the RETURNING list is identical to that
of the output list of SELECT.
You must have the DELETE privilege on the table to delete from it, as well as the SELECT privilege for any table in the USING clause or
whose values are read in the condition.
The WITH clause allows you to specify one or more subqueries that can be referenced by name in the DELETE query. See Section 7.8, "WITH
Queries (Common Table Expressions)", in the documentation and SELECT(7) for details.
The name (optionally schema-qualified) of the table to delete rows from. If ONLY is specified before the table name, matching rows are
deleted from the named table only. If ONLY is not specified, matching rows are also deleted from any tables inheriting from the named
table. Optionally, * can be specified after the table name to explicitly indicate that descendant tables are included.
A substitute name for the target table. When an alias is provided, it completely hides the actual name of the table. For example, given
DELETE FROM foo AS f, the remainder of the DELETE statement must refer to this table as f not foo.
A list of table expressions, allowing columns from other tables to appear in the WHERE condition. This is similar to the list of tables
that can be specified in the FROM Clause of a SELECT statement; for example, an alias for the table name can be specified. Do not
repeat the target table in the using_list, unless you wish to set up a self-join.
An expression that returns a value of type boolean. Only rows for which this expression returns true will be deleted.
The name of the cursor to use in a WHERE CURRENT OF condition. The row to be deleted is the one most recently fetched from this cursor.
The cursor must be a non-grouping query on the DELETE's target table. Note that WHERE CURRENT OF cannot be specified together with a
Boolean condition. See DECLARE(7) for more information about using cursors with WHERE CURRENT OF.
An expression to be computed and returned by the DELETE command after each row is deleted. The expression can use any column names of
the table named by table_name or table(s) listed in USING. Write * to return all columns.
A name to use for a returned column.
On successful completion, a DELETE command returns a command tag of the form
The count is the number of rows deleted. Note that the number may be less than the number of rows that matched the condition when deletes
were suppressed by a BEFORE DELETE trigger. If count is 0, no rows were deleted by the query (this is not considered an error).
If the DELETE command contains a RETURNING clause, the result will be similar to that of a SELECT statement containing the columns and
values defined in the RETURNING list, computed over the row(s) deleted by the command.
PostgreSQL lets you reference columns of other tables in the WHERE condition by specifying the other tables in the USING clause. For
example, to delete all films produced by a given producer, one can do:
DELETE FROM films USING producers
WHERE producer_id = producers.id AND producers.name = 'foo';
What is essentially happening here is a join between films and producers, with all successfully joined films rows being marked for
deletion. This syntax is not standard. A more standard way to do it is:
DELETE FROM films
WHERE producer_id IN (SELECT id FROM producers WHERE name = 'foo');
In some cases the join style is easier to write or faster to execute than the sub-select style.
Delete all films but musicals:
DELETE FROM films WHERE kind <> 'Musical';
Clear the table films:
DELETE FROM films;
Delete completed tasks, returning full details of the deleted rows:
DELETE FROM tasks WHERE status = 'DONE' RETURNING *;
Delete the row of tasks on which the cursor c_tasks is currently positioned:
DELETE FROM tasks WHERE CURRENT OF c_tasks;
This command conforms to the SQL standard, except that the USING and RETURNING clauses are PostgreSQL extensions, as is the ability to use
WITH with DELETE.
PostgreSQL 9.2.7 2014-02-17 DELETE(7)