redhat man page for update

UPDATE(7)							   SQL Commands 							 UPDATE(7)

NAME
       UPDATE - update rows of a table

SYNOPSIS
       UPDATE [ ONLY ] table SET col = expression [, ...]
	   [ FROM fromlist ]
	   [ WHERE condition ]

   INPUTS
       table  The name (optionally schema-qualified) of an existing table. If ONLY is specified, only that table is updated. If ONLY is not speci-
	      fied, the table and all its descendant tables (if any) are updated. * can be appended to the table name to indicate that	descendant
	      tables  are  to  be scanned, but in the current version, this is the default behavior. (In releases before 7.1, ONLY was the default
	      behavior.) The default can be altered by changing the SQL_INHERITANCE configuration option.

       column The name of a column in table.

       expression
	      A valid expression or value to assign to column.

       fromlist
	      A PostgreSQL non-standard extension to allow columns from other tables to appear in the WHERE condition.

       condition
	      Refer to the SELECT statement for a further description of the WHERE clause.

   OUTPUTS
       UPDATE #
	      Message returned if successful.  The # means the number of rows updated.	If # is 0 no rows are updated.

DESCRIPTION
       UPDATE changes the values of the columns specified for all rows which satisfy condition. Only the columns to be	modified  need	appear	as
       columns in the statement.

       Array  references use the same syntax found in SELECT [select(7)].  That is, either single array elements, a range of array elements or the
       entire array may be replaced with a single query.

       You must have write access to the table in order to modify it, as well as read access to any table whose values are mentioned in the  WHERE
       condition.

       By  default  UPDATE  will  update  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.

USAGE
       Change word Drama with Dramatic on column kind:

       UPDATE films
       SET kind = 'Dramatic'
       WHERE kind = 'Drama';
       SELECT *
       FROM films
       WHERE kind = 'Dramatic' OR kind = 'Drama';

	code  |     title     | did | date_prod  |   kind   | len
       -------+---------------+-----+------------+----------+-------
	BL101 | The Third Man | 101 | 1949-12-23 | Dramatic | 01:44
	P_302 | Becket	      | 103 | 1964-02-03 | Dramatic | 02:28
	M_401 | War and Peace | 104 | 1967-02-12 | Dramatic | 05:57
	T_601 | Yojimbo       | 106 | 1961-06-16 | Dramatic | 01:50
	DA101 | Das Boot      | 110 | 1981-11-11 | Dramatic | 02:29

COMPATIBILITY
   SQL92
       SQL92 defines a different syntax for the positioned UPDATE statement:

       UPDATE table SET column = expression [, ...]
	   WHERE CURRENT OF cursor

       where cursor identifies an open cursor.

SQL - Language Statements					    2002-11-22								 UPDATE(7)