oracle12c，sql，组

Question

原始sql是：

select c.col1,a.col2,count(1) from table_1 a,table_2 b.table_3 c where a.key =b.key and b.no = c.no group by c.col1,a.col2 having count(a.col2) >1;

产出：

c.col1  a.col2 count(1)
aa1     bb1    2
aa1     bb2    3
aa1     bb3    5
aa2     bb8    1
aa2     bb1    4

我试着得到输出集，如下所示

c.col1   count(1)
aa1        10
aa2        5

如何编写sql？

Answer 1

“简单”选项是将当前查询(重写为使用JOIN，这是当今连接表的首选方式)作为内联视图使用：

  SELECT col1, SUM (cnt)
    FROM (  SELECT c.col1, a.col2, COUNT (*) cnt     --> your current query begins here
              FROM table_1 a
                   JOIN table_2 b ON a.key = b.key
                   JOIN table_3 c ON c.no = b.no
          GROUP BY c.col1, a.col2
            HAVING COUNT (a.col2) > 1)               --> and ends here
GROUP BY col1;

或者，从a.col2中删除select

  SELECT c.col1, COUNT (*) cnt
    FROM table_1 a
         JOIN table_2 b ON a.key = b.key
         JOIN table_3 c ON c.no = b.no
GROUP BY c.col1, a.col2
  HAVING COUNT (a.col2) > 1;

Answer 2

我相信，如果您只需从select和group中删除col2，您就可以做到这一点。因为col2将不再被返回，所以您还应该删除having语句。我觉得应该是这样的：

select
    c.col1,
    count(1)
from
    table_1 a,
    table_2 b,
    table_3 c
where
    a.key = b.key
    and b.no = c.no
group by
    c.col1;

我希望这能帮到你。

Answer 3

对col1使用sum()和只组by

select c.col1, sum(a.col2) as total
    from table_1 a,table_2 b.table_3 c 
    where a.key =b.key and b.no = c.no 
    group by c.col1;

输出--

c.col1   total
aa1        10
aa2        5