[英]SQL - identifying rows for a value in one table, where all joined rows only has a specific value
在SQL Server中,我有一个加入了many:many关系的结果集。
考虑通过链接表链接到订单的产品,
Table - Products
ID
ProductName
Table - Orders
ID
OrderCountry
LinkTable OrderLines (columns not shown)
我希望能够过滤这些结果,以仅显示对于一个表中的实体,另一表中的所有值在特定列中仅具有给定值的结果。 就我的示例而言,对于每种产品,当它们链接到的所有订单都针对国家/地区时,我只想返回联接的行
因此,如果我的链接结果集是
productid, product, orderid, ordercountry
1, Chocolate, 1, uk
2, Banana, 2, uk
2, Banana, 3, usa
3, Strawberry, 4, usa
我要过滤,以便仅显示那些仅在英国订购的产品(即巧克力)。 我敢肯定这应该是直接的,但是今天星期五下午和我大脑的SQL部分已经放弃了……
您可以执行以下操作,首先获得仅在一个国家/地区销售的所有产品,然后继续获取这些产品的所有订单
with distinctProducts as
(
select LinkTable.ProductID
from Orders
inner join LinkTable on LinkTable.OrderID = Orders.ID
group by LinkTable.ProductID
having count(distinct Orders.OrderCountry) = 1
)
select pr.ID as ProductID
,pr.ProductName
,o.ID as OrderID
,o.OrderCountry
from Products pr
inner join LinkTable lt on lt.ProductID = pr.ID
inner join Orders o on o.ID = lt.OrderID
inner join distinctProducts dp on dp.ProductID = pr.ID
where o.OrderCountry = 'UK'
嗯 根据Philip的早期方法,请尝试添加以下类似内容,以排除在其他国家/地区订购相同产品的行:
SELECT pr.Id, pr.ProductName, od.Id, od.OrderCountry
from Products pr
inner join LinkTable lt
on lt.ProductId = pr.ID
inner join Orders od
on od.ID = lt.OrderId
where
od.OrderCountry = 'UK'
AND NOT EXISTS
(
SELECT
*
FROM
Products MatchingProducts
inner join LinkTable lt
on lt.ProductId = MatchingProducts.ID
inner join Orders OrdersFromOtherCountries
on OrdersFromOtherCountries.ID = lt.OrderId
WHERE
MatchingProducts.ID = Pr.ID AND
OrdersFromOtherCountries.OrderCountry != od.OrderCountry
)
希望其中一些可以普遍重用:
;with startingRS (productid, product, orderid, ordercountry) as (
select 1, 'Chocolate', 1, 'uk' union all
select 2, 'Banana', 2, 'uk' union all
select 2, 'Banana', 3, 'usa' union all
select 3, 'Strawberry', 4, 'usa'
), countryRankings as (
select productid,product,orderid,ordercountry,
RANK() over (PARTITION by productid ORDER by ordercountry) as FirstCountry,
RANK() over (PARTITION by productid ORDER by ordercountry desc) as LastCountry
from
startingRS
), singleCountry as (
select productid,product,orderid,ordercountry
from countryRankings
where FirstCountry = 1 and LastCountry = 1
)
select * from singleCountry where ordercountry='uk'
在startingRS中,您将放置当前必须生成的中间结果的任何查询。 countryRankings CTE添加了两个新列,用于对每个productid中的国家/地区进行排名。
singleCountry CTE将结果集缩减为那些国家/地区在生产ID中既是第一个国家又是最后一个国家(即,该生产ID中只有一个国家)的结果。 最后,我们查询仅来自英国的结果。
例如,如果您想要所有具有单个原产国的productid行,则只需跳过最后一个where子句(结果中还会得到3,strawberry,4,usa)。
因此,您是否有一个当前查询,如下所示:
select p.productid,p.product,o.orderid,o.ordercountry
from product p inner join order o on p.productid = o.productid --(or however these joins work for your tables)
然后,您将第一个CTE重写为:
;with startingRS (productid, product, orderid, ordercountry) as (
select p.productid,p.product,o.orderid,o.ordercountry
from product p inner join order o on p.productid = o.productid
), /* rest of query */
;WITH mytable (productid,ordercountry)
AS
(SELECT productid, ordercountry
FROM Orders od INNER JOIN LinkTable lt ON od.orderid = lt.OrderId)
SELECT * FROM mytable
INNER JOIN dbo.Products pr ON pr.productid = mytable.productid
WHERE pr.productid NOT IN (SELECT productid FROM mytable
GROUP BY productid
HAVING COUNT(ordercountry) > 1)
AND ordercountry = 'uk'
SELECT pr.Id, pr.ProductName, od.Id, od.OrderCountry
from Products pr
inner join LinkTable lt
on lt.ProductId = pr.ID
inner join Orders od
on od.ID = lt.OrderId
where od.OrderCountry = 'UK'
这可能不是最有效的方法,但是...
SELECT p.ProductName
FROM Product p
WHERE p.ProductId IN
(
SELECT DISTINCT ol.ProductId
FROM OrderLines ol
INNER JOIN [Order] o
ON ol.OrderId = o.OrderId
WHERE o.OrderCountry = 'uk'
)
AND p.ProductId NOT IN
(
SELECT DISTINCT ol.ProductId
FROM OrderLines ol
INNER JOIN [Order] o
ON ol.OrderId = o.OrderId
WHERE o.OrderCountry != 'uk'
)
测试数据
create table product
(
ProductId int,
ProductName nvarchar(50)
)
go
create table [order]
(
OrderId int,
OrderCountry nvarchar(50)
)
go
create table OrderLines
(
OrderId int,
ProductId int
)
go
insert into Product VALUES (1, 'Chocolate')
insert into Product VALUES (2, 'Banana')
insert into Product VALUES (3, 'Strawberry')
insert into [order] values (1, 'uk')
insert into [order] values (2, 'uk')
insert into [order] values (3, 'usa')
insert into [order] values (4, 'usa')
insert into [orderlines] values (1, 1)
insert into [orderlines] values (2, 2)
insert into [orderlines] values (3, 2)
insert into [orderlines] values (4, 3)
insert into [orderlines] values (3, 2)
insert into [orderlines] values (3, 3)
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