Index: src/func.c
==================================================================
--- src/func.c
+++ src/func.c
@@ -14,11 +14,11 @@
 **
 ** There is only one exported symbol in this file - the function
 ** sqliteRegisterBuildinFunctions() found at the bottom of the file.
 ** All other code has file scope.
 **
-** $Id: func.c,v 1.211 2009/01/24 11:30:43 drh Exp $
+** $Id: func.c,v 1.212 2009/02/01 18:08:41 drh Exp $
 */
 #include "sqliteInt.h"
 #include <stdlib.h>
 #include <assert.h>
 #include "vdbeInt.h"
@@ -818,11 +818,19 @@
   zStr = sqlite3_value_text(argv[0]);
   if( zStr==0 ) return;
   nStr = sqlite3_value_bytes(argv[0]);
   assert( zStr==sqlite3_value_text(argv[0]) );  /* No encoding change */
   zPattern = sqlite3_value_text(argv[1]);
-  if( zPattern==0 || zPattern[0]==0 ) return;
+  if( zPattern==0 ){
+    assert( sqlite3_value_type(argv[1])==SQLITE_NULL );
+    return;
+  }
+  if( zPattern[0]==0 ){
+    assert( sqlite3_value_type(argv[1])!=SQLITE_NULL );
+    sqlite3_result_value(context, argv[0]);
+    return;
+  }
   nPattern = sqlite3_value_bytes(argv[1]);
   assert( zPattern==sqlite3_value_text(argv[1]) );  /* No encoding change */
   zRep = sqlite3_value_text(argv[2]);
   if( zRep==0 ) return;
   nRep = sqlite3_value_bytes(argv[2]);

Index: test/func.test
==================================================================
--- test/func.test
+++ test/func.test
@@ -9,11 +9,11 @@
 #
 #***********************************************************************
 # This file implements regression tests for SQLite library.  The
 # focus of this file is testing built-in functions.
 #
-# $Id: func.test,v 1.88 2009/01/31 22:28:49 drh Exp $
+# $Id: func.test,v 1.89 2009/02/01 18:08:41 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
 
 # Create a table to work with.
@@ -360,21 +360,21 @@
   do_test func-9.11-utf16le {
     execsql {SELECT hex(replace('abcdefg','ef','12'))}
   } {6100620063006400310032006700}
   do_test func-9.12-utf16le {
     execsql {SELECT hex(replace('abcdefg','','12'))}
-  } {{}}
+  } {6100620063006400650066006700}
   do_test func-9.13-utf16le {
     execsql {SELECT hex(replace('aabcdefg','a','aaa'))}
   } {610061006100610061006100620063006400650066006700}
 } elseif {$encoding=="UTF-8"} {
   do_test func-9.11-utf8 {
     execsql {SELECT hex(replace('abcdefg','ef','12'))}
   } {61626364313267}
   do_test func-9.12-utf8 {
     execsql {SELECT hex(replace('abcdefg','','12'))}
-  } {{}}
+  } {61626364656667}
   do_test func-9.13-utf8 {
     execsql {SELECT hex(replace('aabcdefg','a','aaa'))}
   } {616161616161626364656667}
 }