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DELETE()			 SQL Commands			      DELETE()

NAME
       DELETE - delete rows of a table

SYNOPSIS
       DELETE FROM [ ONLY ] table [ [ AS ] alias ]
	   [ USING usinglist ]
	   [ WHERE condition | WHERE CURRENT OF cursor_name ]
	   [ RETURNING * | output_expression [ AS output_name ] [, ...] ]

DESCRIPTION
       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.

	      Tip:  TRUNCATE [truncate(7)] is a PostgreSQL extension that pro‐
	      vides a faster mechanism to remove all rows from a table.

       By default, DELETE will delete rows in the specified table and all  its
       child  tables.  If you wish to delete only from the specific table men‐
       tioned, you must use the ONLY clause.

       There are two ways to delete rows in a  table  using  information  con‐
       tained  in other tables in the database: using sub-selects, or specify‐
       ing 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.

PARAMETERS
       ONLY   If  specified,  delete  rows from the named table only. When not
	      specified, any tables inheriting from the named table  are  also
	      processed.

       table  The name (optionally schema-qualified) of an existing table.

       alias  A	 substitute  name  for the target table. When an alias is pro‐
	      vided, 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.

       usinglist
	      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 [select(7)] of a
	      SELECT  statement;  for example, an alias for the table name can
	      be specified. Do not repeat the target table in  the  usinglist,
	      unless you wish to set up a self-join.

       condition
	      An  expression  that returns a value of type boolean.  Only rows
	      for which this expression returns true will be deleted.

       cursor_name
	      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  simple  (non-join,	non-aggregate)
	      query  on the DELETE's target table.  Note that WHERE CURRENT OF
	      cannot be specified together with a Boolean condition.

       output_expression
	      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 or table(s) listed  in	 USING.	  Write	 *  to
	      return all columns.

       output_name
	      A name to use for a returned column.

OUTPUTS
       On successful completion, a DELETE command returns a command tag of the
       form

       DELETE count

       The count is the number of rows deleted. If count is 0, no rows matched
       the condition (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.

NOTES
       PostgreSQL lets you reference columns of other tables in the WHERE con‐
       dition 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  produc‐
       ers, 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.

EXAMPLES
       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 posi‐
       tioned:

       DELETE FROM tasks WHERE CURRENT OF c_tasks;

COMPATIBILITY
       This command conforms to the SQL standard, except that  the  USING  and
       RETURNING clauses are PostgreSQL extensions.

SQL - Language Statements	  2008-02-01			      DELETE()
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