--- pgadmin3-1.22.0.orig/pgadmin/dlg/dlgCast.cpp
+++ pgadmin3-1.22.0/pgadmin/dlg/dlgCast.cpp
@@ -157,7 +157,7 @@ void dlgCast::OnChangeType(wxCommandEven
 		    wxT("  JOIN pg_namespace n ON n.oid=pronamespace\n")
 		    wxT(" WHERE proargtypes[0] = ")
 		    +  GetTypeOid(cbSourceType->GetGuessedSelection())
-		    +  wxT("\n   AND proargtypes[1] = 0")
+		    +  wxT("\n   AND pronargs = 1")
 		    wxT("\n   AND prorettype = ")
 		    +  GetTypeOid(cbTargetType->GetGuessedSelection());