diff -Nurb ../postgresql-7.4.2.orig/src/backend/utils/adt/numutils.c ./src/backend/utils/adt/numutils.c
--- ../postgresql-7.4.2.orig/src/backend/utils/adt/numutils.c	2003-09-25 08:58:04.000000000 +0200
+++ ./src/backend/utils/adt/numutils.c	2004-04-30 11:37:35.977932032 +0200
@@ -43,6 +43,9 @@
 #endif
 
 
+bool empty_equals_0;
+
+
 /*
  * pg_atoi: convert string to integer
  *
@@ -67,6 +70,9 @@
 	if (s == (char *) NULL)
 		elog(ERROR, "NULL pointer");
 	if (*s == 0)
+		if(empty_equals_0)
+			return (int32)0;
+        else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
 				 errmsg("invalid input syntax for integer: \"%s\"",
diff -Nurb ../postgresql-7.4.2.orig/src/backend/utils/misc/guc.c ./src/backend/utils/misc/guc.c
--- ../postgresql-7.4.2.orig/src/backend/utils/misc/guc.c	2004-02-23 21:46:16.000000000 +0100
+++ ./src/backend/utils/misc/guc.c	2004-04-30 11:28:31.302735248 +0200
@@ -73,6 +73,7 @@
 extern int	CommitDelay;
 extern int	CommitSiblings;
 extern char *preload_libraries_string;
+extern int  empty_equals_0;
 
 #ifdef HAVE_SYSLOG
 extern char *Syslog_facility;
@@ -748,6 +749,14 @@
 		true, NULL, NULL
 	},
 	{
+		{"empty_equals_0", PGC_USERSET, COMPAT_OPTIONS_PREVIOUS,
+			gettext_noop("Treats the empty string as 0 when dealing with integers"),
+			NULL
+		},
+		&empty_equals_0,
+		false, NULL, NULL
+	},
+	{
 		{"australian_timezones", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Interprets ACST, CST, EST, and SAT as Australian time zones."),
 			gettext_noop("Otherwise they are interpreted as North/South American "
diff -Nurb ../postgresql-7.4.2.orig/src/bin/psql/tab-complete.c ./src/bin/psql/tab-complete.c
--- ../postgresql-7.4.2.orig/src/bin/psql/tab-complete.c	2003-11-08 21:54:37.000000000 +0100
+++ ./src/bin/psql/tab-complete.c	2004-04-30 11:36:41.703183048 +0200
@@ -501,6 +501,7 @@
 		"default_transaction_read_only",
 		"dynamic_library_path",
 		"effective_cache_size",
+		"empty_equals_0",
 		"enable_hashagg",
 		"enable_hashjoin",
 		"enable_indexscan",