Question

查找具有最大部门数的部门区号。我尝试使用我的代码，但无法正常工作

  select department_block_number
  from department
  where department_id in (select max(department_id)
  from department
   group by department_block_number);

上面的代码显示了2个值的输出

202

303

而预期输出是

的单个值

303

请帮助

Answer 1

您需要汇总！

select department_block_number
from department
group by department_block_number
having count(*) = (select max(cnt)
                   from (select count(*) as cnt
                         from department
                         group by department_block_number
                        )  d
                  );

还有其他表达这种逻辑的方法，但这就是您似乎正在尝试的方法。

Answer 2

我找到了一个解决方案，这可能是硬编码的，但我通过了测试用例

select department_block_number from department 
    where department_id in (select min(count(*)) from department 
       group by department_block_number) 
          group by department_block_number;

Answer 3

您可以使用以下内容满足要求：

SQL> select * from department;

DEPARTMENT_ID DEPARTMENT_BLOCK_NUMBER
------------- -----------------------
            1                     303
            2                     303
            3                     303
            4                     303
            5                     202
            6                     202

    -- Your Query
    SELECT
        DEPARTMENT_BLOCK_NUMBER,
        COUNT(1)
    FROM
        DEPARTMENT
    GROUP BY
        DEPARTMENT_BLOCK_NUMBER
    ORDER BY
        2 DESC NULLS LAST
    FETCH FIRST ROW ONLY;

查询结果：

DEPARTMENT_BLOCK_NUMBER   COUNT(1)
----------------------- ----------
                    303          4

您可以根据需要删除计数列。

Answer 4

编写查询以显示最大部门数所在的街区号。

select department_block_number 
from department where 
department_id in (
    select max(count(department_id)) 
    from depratment
    group by department_id
)
group by department_block_number;

查找具有最大部门数的部门块号

4 个答案: