Question

我必须检索一些数据（Oracle RDBMS）。我必须过滤它们，给它们加油。所以我想做三个嵌套查询从外部开始：用于限制查询以对其进行排序的查询和用于选择的查询（还对其进行过滤和分组）。这是查询：

    @SqlQuery("select count(*) personCount, SURNAME surname, SKILL skill, ROWNUM " +
        "     from (select * " +
        "        from (select count(*) personCount, SURNAME surname, SKILL skill from people " +
        "           where ....my filters....
        "          group by SURNAME, SKILL ) " +
        "       order by personCount DESC )  " +
        "     where ROWNUM \\<= :limit ")

但它给了我这个错误：ORA-00937: it is not a group function on only one grouping

为什么？

Answer 1

您不能在外部选择中进行计数：

   @SqlQuery("select personCount, surname, skill, ROWNUM " +
        "     from (select * " +
        "        from (select count(*) personCount, SURNAME surname, SKILL skill from people " +
        "           where ....my filters.... "
        "          group by SURNAME, SKILL) " +
        "       order by personCount DESC )  " +
        "     where ROWNUM \\<= :limit ")

Answer 2

您必须指定在group by子句中选择的所有列：

    @SqlQuery("select personCount, SURNAME surname, SKILL skill, ROWNUM " +
        "     from (select * " +
        "        from (select count(*) personCount, SURNAME surname, SKILL skill from people " +
        "           where ....my filters.... " +
        "          group by SURNAME, SKILL ) " +
        "       order by personCount DESC )  " +
        "     where ROWNUM \\<= :limit ")

此外，您已计算了personCount的计数，您无需再次计算。

请注意，我将知识列替换为组中的技能列，我认为这是一个错字。

ORA-00937：它不仅仅是一个分组的组功能

2 个答案: