select ArticleID,ChannelID,ClassID,Title,Author,Hits,UpdateTime,DefaultPicUrl,Stars from PE_Article where ArticleID={input(0)}如何讓它在DefaultPicUrl不存在的時候顯示另外一張圖片？？？？添加成select ArticleID,ChannelID,ClassID,Title,Author,Hits,UpdateTime,DefaultPicUrl,Stars from PE_Article where ArticleID={input(0)} and DefaultPicUrl is not null order by ArticleID desc也不行用if ??不知道格式是怎樣的。請給出解答。