我想调取news表中PhotoUser字段不为空的记录,PhotoUser表为文本型,是个图片路径字段,这个查询语句改怎么写呢,PhotoUser Is Null这样写调取的内容不对sql="select top 1 * from News where ViewFlagch and PhotoUser Is Null and Instr(SortPath,'"&SortPath&"')>0 order by id desc"