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DELETE()
NAME
  DELETE - delete rows of a table

SYNOPSIS
  DELETE FROM [ ONLY ] table [ [ AS ] alias ]
      [ USING usinglist ]
      [ WHERE condition ]
      [ 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(5)] 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(5)] 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 returning a value of type boolean, which determines the
       rows that are to be deleted.

  output_expression
       An expression to be computed and returned by the DELETE command after
       each row is deleted. The expression may 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 might 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 *;

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

Index for Section 5

Alphabetical listing for D

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