oracle执行ST_Contains时报错

我在执行下面这条语句时，报以下错误：
select a.fldid
                     from SDE.TGXD_GIS a
                    where sde.ST_Contains(sde.st_buffer(sde.st_point(521098.5096447982,
                                                                     4333993.735339258,
                                                                     3),
                                                        20),a.shape) = 1



请指教！