Question

我有两个“一对多”关系的表。

TblProjects
 ProjectID
 .........

TblCustomers
 ProjectID
 Number
 .........

如何获得所有 ProjectIDs满足此条件的所有Customers

Number % 100 = 0

Answer 1

一般解决方案是使用queue.take()反向条件（NOT EXISTS而不是<>）：

这是SQLFiddle。

或者，特定于此用例，您可以使用更简洁的查询：

SELECT DISTINCT p.ProjectID
FROM TblProjects p INNER JOIN TblCustomers ct
  ON ct.ProjectID = p.ProjectID
WHERE NOT EXISTS
  (SELECT 1
   FROM TblCustomers c
   WHERE c.ProjectID = p.ProjectID AND (Number % 100) <> 0)

这是SQLFiddle。

P.S。如果仅需要SELECT p.ProjectID FROM TblProjects p INNER JOIN TblCustomers ct ON ct.ProjectID = p.ProjectID GROUP BY p.ProjectID HAVING MAX(ct.Number % 100) = 0，则根本不需要加入任何内容，只需直接使用ProjectID即可。

Answer 2

您可以使用内连接

Select * from tblProjects pro
inner join tblCustomers cst on pro.projectID = cst.ProjectID 
and cst.Number % 100 = 0

它将为您提供您所要求的内容

Answer 3

你可以使用CTE来获取可读的查询：

;with 

not_all_at_100 as
( select distinct c.ProjectID
  FROM TblCustomers c
  WHERE (c.Number % 100) != 0
),

all_project_customers as 
( select ProjectID
  FROM TblCustomers 
)

select distinct p.ProjectID
from TblProjects p
where p.ProjectID in  ( select ProjectID from all_project_customers )
  and p.ProjectID not in ( select ProjectID from not_all_at_100 )

如何选择所有子项在SQL中满足条件的父行？

3 个答案: