Access sql中的嵌套IF语句（asp经典）

Question

我想找到一种方法在我的ADO对象中使用IF语句合并以下4个查询（在mdb数据库上）

    SELECT * FROM promo WHERE cocategory = 'ri' and codart = '00010089' and costart <= date() and coend >= date() and copre >= 1 order by copre asc
    SELECT * FROM promo WHERE cocategory = 'ri' and codart = '00010089' and costart <= date() and coend >= date() and copr is not null
    SELECT * FROM milis WHERE codelis = '3' and codart = '00010089' and listart < date() and liend > date() and liqta > 0 order by liqta asc
    SELECT * FROM milis WHERE codelis = '3' and codart = '00010089' and listart < date() and liend > date()

从第一个查询获取EOF（空），获取第二个等等......直到其中一个返回记录。