Provided by: postgresql-client-8.4_8.4.4-2_i386 bug

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
              provides 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
       mentioned, you must use the ONLY clause.

       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.

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
              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.

       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 non-grouping query on the  DELETE’s
              target  table.   Note  that WHERE CURRENT OF cannot be specified
              together with a Boolean condition. See DECLARE [declare(7)]  for
              more information about using cursors with WHERE CURRENT OF.

       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
       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.

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
       positioned:

       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.