Question

这个SQL：

select Name,
       (select COUNT(1) from tbl_projects where statusId = tbl_sections.StatusId) as N
from tbl_sections
left join tbl_section_names on tbl_section_names.Id = NameId

生成以下数据：

Name    N
Completed   133
Cancelled   100
Unassigned  1
Sales   49
Development 10
Development 4
Development 1

我正在尝试修改它，以便按如下方式返回数据：

Name    N
Completed   133
Cancelled   100
Unassigned  1
Sales   49
Development 15

（即，总结名称相同的行）

有人能提出一些关于如何使这项工作的线索吗？我猜我需要一个SUM和一个GROUP BY，但它甚至都没有运行查询，因为我得到的只是错误。

Answer 1

尝试此查询。它汇总N按Name分组。

SELECT Name, SUM(N) 
FROM (
    SELECT Name,
    (SELECT COUNT(1) 
        FROM tbl_projects 
        WHERE statusId = tbl_sections.StatusId
    ) AS N
    FROM tbl_sections
    LEFT JOIN tbl_section_names ON tbl_section_names.Id = NameId
) a
GROUP BY a.Name

Answer 2

试试这个

select Name, count(p.statusid) N
from tbl_sections
left join tbl_section_names on tbl_section_names.Id = NameId
left outer join tbl_projects p on tbl_sections.StatusId = p.statusId 
group by Name

Answer 3

Select Name, Sum(N) from
    (select Name,
       (select COUNT(1) from tbl_projects where statusId = tbl_sections.StatusId) as N
    from tbl_sections
    left join tbl_section_names on tbl_section_names.Id = NameId)
group by Name

Answer 4

此查询为您提供每个状态的计数，这意味着开发具有三个不同状态的部分，并且查询将反映这一点，如果您将状态添加为列，则更有意义：

select Name, tbl_sections.StatusId,
       (select COUNT(1) from tbl_projects where statusId = tbl_sections.StatusId) as N
from tbl_sections
left join tbl_section_names on tbl_section_names.Id = NameId

我不知道你的数据库的结构，但如果你想要计算每个名字的节数，可能是这样的。这基本上将查看连接的结果，然后通过告诉您每个唯一名称出现的次数来总结它：

select Name, count(*)
from tbl_sections
left join tbl_section_names on tbl_section_names.Id = NameId
Group By Name

Answer 5

尝试一下。

select Name,
   SUM(select COUNT(1) from tbl_projects where statusId = tbl_sections.StatusId) as N
from tbl_sections
left join tbl_section_names on tbl_section_names.Id = NameId
group by Name

SQL按ID分组的行总和

5 个答案: