|
|
My Five Minutes of Musical Fame
|
|
DELETE(7) SQL Commands DELETE(7) NAME
DELETE - delete rows of a table SYNOPSIS
DELETE FROM [ ONLY ] table [ WHERE condition ] INPUTS table The name (optionally schema-qualified) of an existing table. condition This is an SQL selection query which returns the rows which are to be deleted. Refer to the SELECT statement for further description of the WHERE clause. OUTPUTS DELETE count Message returned if items are successfully deleted. The count is the number of rows deleted. If count is 0, no rows were deleted. DESCRIPTION
DELETE removes rows which satisfy the WHERE clause from the specified table. If the condition (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 which provides a faster mechanism to remove all rows from a table. By default DELETE will delete tuples in the table specified and all its sub-tables. If you wish to only update the specific table men- tioned, you should use the ONLY clause. You must have write access to the table in order to modify it, as well as read access to any table whose values are read in the condition. USAGE
Remove all films but musicals: DELETE FROM films WHERE kind <> 'Musical'; SELECT * FROM films; code | title | did | date_prod | kind | len -------+---------------------------+-----+------------+---------+------- UA501 | West Side Story | 105 | 1961-01-03 | Musical | 02:32 TC901 | The King and I | 109 | 1956-08-11 | Musical | 02:13 WD101 | Bed Knobs and Broomsticks | 111 | | Musical | 01:57 (3 rows) Clear the table films: DELETE FROM films; SELECT * FROM films; code | title | did | date_prod | kind | len ------+-------+-----+-----------+------+----- (0 rows) COMPATIBILITY
SQL92 SQL92 allows a positioned DELETE statement: DELETE FROM table WHERE CURRENT OF cursor where cursor identifies an open cursor. Interactive cursors in PostgreSQL are read-only. SQL - Language Statements 2002-11-22 DELETE(7)
