fixed issue topic/web2py/UnN6AyOh2Lg thanks Paul

gluon/sqlhtml.py

@@ -1939,11 +1939,13 @@ class SQLFORM(FORM):
             if settings.global_settings.web2py_runtime_gae:
                 return reduce(lambda a,b: a|b, [field.contains(key) for field in sfields])
             else:
+                if not (sfields and key and key.split()):
+                    return fields[0].table
                 return reduce(lambda a,b:a&b,[
                         reduce(lambda a,b: a|b, [
                                 field.contains(k) for field in sfields]
                                ) for k in key.split()])
-
+                    
             # from https://groups.google.com/forum/#!topic/web2py/hKe6lI25Bv4
             # needs testing...
             #words = key.split(' ') if key else []