ORA-00937: 它不是仅在一个分组上的组函数

Question

我必须检索一些数据 (Oracle RDBMS)。我必须过滤它们，将它们分组。所以我想做三个嵌套查询。
从外到内：限制查询对它们进行排序的查询和选择查询（也对它们进行过滤和分组）。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

您不能在外部进行计数 select:

   @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

您必须在 group by 子句中指定 select 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 ")

另外，personCount的个数您已经统计过了，不用再统计了。

注意我在group by中把knowledge栏换成了skill栏，我以为是打错了。

ORA-00937: 它不是仅在一个分组上的组函数

ORA-00937: it is not a group function on only one grouping

sql

oracle

rdbms

group-by