Allow extract() to accept the same field selectors as date_part(), not just

the ones specified by SQL.

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.220 2001/02/09 03:26:28 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.221 2001/02/18 18:06:10 petere Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -4987,6 +4987,7 @@ extract_list:  extract_arg FROM a_expr
 		;
 
 extract_arg:  datetime						{ $$ = $1; }
+		| IDENT						{ $$ = $1; }
 		| TIMEZONE_HOUR						{ $$ = "tz_hour"; }
 		| TIMEZONE_MINUTE					{ $$ = "tz_minute"; }
 		;