获取每个Customer的first和last Order以及每个订单中价值最高的Item，都是单独的表
Get first and last Order and the highest value Item in each order for each Customer, all of which are separate tables
我需要按订单日期查找每个客户的第一个和最后一个订单，以及每个订单中业务量最高的商品的名称和 SKU。作为参考，Customer table 有超过 150k 条记录，Orders 和 OrderDetails（这些是 Items）更多。
注意：订单及其各自的项目应与客户位于同一行
订单
OrderID OrderDate CustomerID BusinessVolumeTotal Subtotal
13212 '2021-09-06' 512312 500.00 25.60
订单详情
OrderID ItemCode ItemDescription BusinessVolume
13212 'SKW-BS' 'Some item' 450.00
在我的第一个查询中，我试图坚持使用连接而不是子查询，这导致了这个
select distinct(c.CustomerID), c.FirstName + ' ' + c.LastName as Name,
cs.CustomerStatusDescription as Status,
ct.CustomerTypeDescription as Type, pv.Volume80 as G3,
fo.OrderID,fo.OrderDate,fo.SubTotal,fo.Country, fod.ItemCode, fod.ItemDescription, fopt.PriceTypeID,
lo.OrderID,lo.OrderDate,lo.SubTotal,lo.Country, lod.ItemCode, lod.ItemDescription, lopt.PriceTypeID
from Customers c
left join CustomerTypes ct on ct.CustomerTypeID = c.CustomerTypeID
left join CustomerStatuses cs on cs.CustomerStatusID = c.CustomerStatusID
left join PeriodVolumes pv on pv.CustomerID = c.CustomerID
left join Orders fo on fo.CustomerID = c.CustomerID -- First Order
left join Orders lo on lo.CustomerID = c.CustomerID -- Last Order
left join OrderDetails fod on fod.OrderID = fo.OrderID
left join OrderDetails lod on lod.OrderID = lo.OrderID
left join PriceTypes fopt on fo.PriceTypeID = fopt.PriceTypeID
left join PriceTypes lopt on lo.PriceTypeID = lopt.PriceTypeID
where c.CustomerStatusID in (1,2)
and c.CustomerTypeID in (2,3)
and pv.PeriodTypeID = 2
/* First Order */
and fo.OrderID = (select top 1(OrderID) from Orders where CustomerID = c.CustomerID and OrderStatusID>=7 order by OrderDate )
and fod.ItemID = (select top 1(ItemID) from OrderDetails where OrderID = fo.OrderID order by BusinessVolume)
/* Last Order */
and lo.OrderID = (select top 1(OrderID) from Orders where CustomerID = c.CustomerID and OrderStatusID>=7 order by OrderDate desc)
and lod.ItemID = (select top 1(ItemID) from OrderDetails where OrderID = lo.OrderID order by BusinessVolume desc)
and pv.PeriodID = (select PeriodID from Periods where PeriodTypeID=2 and StartDate <= @now and EndDate >= @now)
但这最终执行了大约 6-7 分钟。从解释计划来看，它看起来大部分被基于 OrderStatusID >= 7 的订单键查找占用。
所以我尝试使用 window 函数来实现相同的目的：
select distinct(c.CustomerID), c.FirstName + ' ' + c.LastName as Name, cs.CustomerStatusDescription as Status,
ct.CustomerTypeDescription as Type, pv.Volume80 as G3,
fal.*
from Customers c
left join CustomerTypes ct on ct.CustomerTypeID = c.CustomerTypeID
left join CustomerStatuses cs on cs.CustomerStatusID = c.CustomerStatusID
left join PeriodVolumes pv on pv.CustomerID = c.CustomerID
left join(
select
CustomerID,
max(case when MinDate = 1 then OrderID end) FirstOrderID,
max(case when MinDate = 1 then OrderDate end) FirstOrderDate,
max(case when MinDate = 1 then BusinessVolumeTotal end) FirstBVTotal,
max(case when MinDate = 1 then PriceTypeDescription end) FirstPriceType,
max(case when MinDate = 1 then ItemCode end) FirstItemCode,
max(case when MinDate = 1 then ItemDescription end) FirstItemDescription,
max(case when MaxDate = 1 then OrderID end) LastOrderID,
max(case when MaxDate = 1 then OrderDate end) LastOrderDate,
max(case when MaxDate = 1 then BusinessVolumeTotal end) LastBVTotal,
max(case when MaxDate = 1 then PriceTypeDescription end) LastPriceType,
max(case when MaxDate = 1 then ItemCode end) LastItemCode,
max(case when MaxDate = 1 then ItemDescription end) LastItemDescription
from
(
select distinct o.CustomerID,
o.OrderID,
o.OrderDate,
o.BusinessVolumeTotal,
PT.PriceTypeDescription,
RANK() over (partition by o.CustomerID order by OrderDate) as MinDate,
RANK() over (partition by o.CustomerID order by OrderDate desc) as MaxDate,
FIRST_VALUE(ItemCode) over (partition by od.OrderID order by BusinessVolume desc) as ItemCode,
FIRST_VALUE(ItemDescription) over (partition by od.OrderID order by BusinessVolume desc) as ItemDescription
from Orders o
left join OrderDetails od on od.OrderID = o.OrderID
left join PriceTypes PT on o.PriceTypeID = PT.PriceTypeID
where o.OrderStatusID >= 7
) fal
group by CustomerID
) fal on c.CustomerId = fal.CustomerID
where c.CustomerStatusID in (1,2)
and c.CustomerTypeID in (2,3)
and pv.PeriodTypeID = 2
/* CurrentG3 */
and pv.PeriodID = (select PeriodID from Periods where PeriodTypeID=2 and StartDate <= @now and EndDate >= @now)
唉，这最终执行的时间更长了。如果可能的话，我需要一种优化方法。
二次查询
我还需要过去 3、6 和 12 个月内每个订单的数量和总和。我目前在原始 returns 结果之后以编程方式作为辅助查询执行此操作，并且我转发 CustomerID，如下所示：
select count(OrderID) as Cnt, sum(BusinessVolumeTotal) as Bv, CustomerID
from Orders where OrderStatusID > 6 and OrderTypeID in (1,4,8,11)
and OrderDate >= @timeAgo and CustomerID in @ids group by CustomerID
乘以 3，因为 3、6 和 12 个月。理想情况下，我也想制作原版的这一部分，但我真的不知道如何去做，尤其是订单的加入是多么复杂。
所以理想情况下我会得到这样的结果 table
CustomerID Name CustomerStatus CustomerType FirstOrderID FirstOrderDate FirstBVTotal FirstItemCode FirstItemDesc FirstPriceType LastOrderID LastOrderDate LastBVTotal LastItemCode LastItemDesc LastPriceType ThreeMonthCount ThreeMonthTotal SixMonthCount SixMonthTotal TwelveMonthCount TwelveMonthTotal
512312 'Jane Doe' 'Active' 'Retail' 13212 '2020-06-06' 50.00 'Item1' 'Item 1 desc' 'Retail' 14321 '2021-09-01' 200.00 'Item2' 'Item 2 desc' 'Retail' 45 4305.00 76 8545.60 183 21542.95
任何关于如何优化或减少查询的帮助和建议，以及任何您认为我做错的事情都将不胜感激。
P.S。我不知道这个标题是否合适以及我是否可以稍后更改它，我已经有一段时间没有使用 SO 来问一个问题了。
更新
查询 1 的实际执行计划：
https://www.brentozar.com/pastetheplan/?id=SJd56RSmK
查询 2 的实际执行计划：
https://www.brentozar.com/pastetheplan/?id=BJ7QHk87Y
我认为您需要牢记此类查询的两个要点：
- window 函数获得良好性能的关键是不要引入不必要的排序。因此，虽然您可以使用
ROW_NUMBER 获得任一方向的第一个订单，但您不应该使用另一个相反的 ROW_NUMBER 获得最后一个。而是使用 LEAD 检查下一行是否存在，从而告诉您这是否是最后一行。然后您可以使用条件聚合。
- 通常有两种计算 first/last 的方法：一种是行编号解决方案，如上所述，另一种是
APPLY，它可以准确地找出您需要的一种。
我认为对于 OrderDetails 我们应该使用申请，因为我们只需要为每个客户查找两个订单。这确实需要良好的索引，因此如果 OrderDetails 没有很好的索引，那么您可能也想为此切换到行编号解决方案。
select
c.CustomerID,
c.FirstName + ' ' + c.LastName as Name,
cs.CustomerStatusDescription as Status,
ct.CustomerTypeDescription as Type,
pv.Volume80 as G3,
o.FirstOrderID,
o.FirstOrderDate,
o.FirstSubTotal,
o.FirstCountry,
fod.ItemCode as FirstItemCode,
fod.ItemDescription as FirstItemDescription,
fopt.PriceTypeDescription as FirstPriceTypeDescription,
o.LastOrderID,
o.LastOrderDate,
o.LastSubTotal,
o.LastCountry,
lod.ItemCode as LastItemCode,
lod.ItemDescription as LastItemDescription,
lopt.PriceTypeDescription as LastPriceTypeDescription
from Customers c
left join CustomerTypes ct on ct.CustomerTypeID = c.CustomerTypeID
left join CustomerStatuses cs on cs.CustomerStatusID = c.CustomerStatusID
left join PeriodVolumes pv on pv.CustomerID = c.CustomerID
and pv.PeriodTypeID = 2
and pv.PeriodID = (
select top 1 PeriodID
from Periods p
where p.PeriodTypeID = 2
and p.StartDate <= @now
and p.EndDate >= @now
)
left join (
select
o.CustomerID,
min(case when rn = 1 then OrderID end) as FirstOrderId,
min(case when rn = 1 then OrderDate end) as FirstOrderDate,
min(case when rn = 1 then SubTotal end) as FirstSubTotal,
min(case when rn = 1 then Country end) as FirstCountry,
min(case when nx is null then OrderID end) as LastOrderId,
min(case when nx is null then OrderDate end) as LastOrderDate,
min(case when nx is null then SubTotal end) as LastSubTotal,
min(case when nx is null then Country end) as LastCountry,
count(case when o.OrderDate >= DATEADD(month, -3, GETDATE()) then 1 end) as ThreeMonthCount,
sum(case when o.OrderDate >= DATEADD(month, -3, GETDATE()) then BusinessVolumeTotal end) as ThreeMonthTotal,
count(case when o.OrderDate >= DATEADD(month, -6, GETDATE()) then 1 end) as SixMonthCount,
sum(case when o.OrderDate >= DATEADD(month, -6, GETDATE()) then BusinessVolumeTotal end) as SixMonthTotal,
count(case when o.OrderDate >= DATEADD(month, -12, GETDATE()) then 1 end) as TwelveMonthCount,
sum(case when o.OrderDate >= DATEADD(month, -12, GETDATE()) then BusinessVolumeTotal end) as TwelveMonthTotal
from (
select *,
ROW_NUMBER() over (partition by o.CustomerID order by OrderDate) as rn,
LEAD(OrderID) over (partition by o.CustomerID order by OrderDate) as nx
from Orders o
where o.OrderStatusID >= 7
and o.OrderTypeID in (1,4,8,11)
and o.OrderDate >= @timeAgo
) o
group by o.CustomerID
) o on o.CustomerID = c.CustomerID
outer apply (
select top 1
od.ItemCode,
od.ItemDescription
from OrderDetails od
order by od.BusinessVolume desc
where od.OrderID = o.FirstOrderId
) fod
outer apply (
select top 1
od.ItemCode,
od.ItemDescription
from OrderDetails od
order by od.BusinessVolume desc
where od.OrderID = o.LastOrderId
) lod
left join PriceTypes fopt on fopt.PriceTypeID = o.FirstPriceTypeID
left join PriceTypes lopt on lopt.PriceTypeID = o.LastPriceTypeID
where c.CustomerStatusID in (1,2)
and c.CustomerTypeID in (2,3);
我也给你一个行编号的版本，从你的执行计划来看，它实际上可能更好。你需要两者都试一下
select
c.CustomerID,
c.FirstName + ' ' + c.LastName as Name,
cs.CustomerStatusDescription as Status,
ct.CustomerTypeDescription as Type,
pv.Volume80 as G3,
o.FirstOrderID,
o.FirstOrderDate,
o.FirstSubTotal,
o.FirstCountry,
o.FirstItemCode,
o.FirstItemDescription,
o.FirstPriceTypeDescription,
o.LastOrderID,
o.LastOrderDate,
o.LastSubTotal,
o.LastCountry,
o.LastItemCode,
o.LastItemDescription,
o.LastPriceTypeDescription
from Customers c
left join CustomerTypes ct on ct.CustomerTypeID = c.CustomerTypeID
left join CustomerStatuses cs on cs.CustomerStatusID = c.CustomerStatusID
left join PeriodVolumes pv on pv.CustomerID = c.CustomerID
and pv.PeriodTypeID = 2
and pv.PeriodID = (
select top 1 PeriodID
from Periods p
where p.PeriodTypeID = 2
and p.StartDate <= @now
and p.EndDate >= @now
)
left join (
select
o.CustomerID,
min(case when rn = 1 then o.OrderID end) as FirstOrderId,
min(case when rn = 1 then o.OrderDate end) as FirstOrderDate,
min(case when rn = 1 then o.SubTotal end) as FirstSubTotal,
min(case when rn = 1 then o.Country end) as FirstCountry,
min(case when rn = 1 then od.ItemCode end) as FirstItemCode,
min(case when rn = 1 then od.ItemDescription end) as FirstItemDescription,
min(case when rn = 1 then opt.PriceTypeDescription end) as FirstPriceTypeDescription,
min(case when nx is null then o.OrderID end) as LastOrderId,
min(case when nx is null then o.OrderDate end) as LastOrderDate,
min(case when nx is null then o.SubTotal end) as LastSubTotal,
min(case when nx is null then o.Country end) as LastCountry,
min(case when nx is null then od.ItemCode end) as LastItemCode,
min(case when nx is null then od.ItemDescription end) as LastItemDescription,
min(case when nx is null then opt.PriceTypeDescription end) as LastPriceTypeDescription,
count(case when o.OrderDate >= DATEADD(month, -3, GETDATE()) then 1 end) as ThreeMonthCount,
sum(case when o.OrderDate >= DATEADD(month, -3, GETDATE()) then BusinessVolumeTotal end) as ThreeMonthTotal,
count(case when o.OrderDate >= DATEADD(month, -6, GETDATE()) then 1 end) as SixMonthCount,
sum(case when o.OrderDate >= DATEADD(month, -6, GETDATE()) then BusinessVolumeTotal end) as SixMonthTotal,
count(case when o.OrderDate >= DATEADD(month, -12, GETDATE()) then 1 end) as TwelveMonthCount,
sum(case when o.OrderDate >= DATEADD(month, -12, GETDATE()) then BusinessVolumeTotal end) as TwelveMonthTotal
from (
select *,
ROW_NUMBER() over (partition by o.CustomerID order by OrderDate) as rn,
LEAD(OrderID) over (partition by o.CustomerID order by OrderDate) as nx
from Orders o
where o.OrderStatusID >= 7
and o.OrderTypeID in (1,4,8,11)
and o.OrderDate >= @timeAgo
) o
left join PriceTypes opt on opt.PriceTypeID = o.PriceTypeID
join (
select *,
ROW_NUMBER() over (partition by od.OrderID order by od.BusinessVolume desc) as rn
from OrderDetails od
) od on od.OrderID = o.OrderId
where rn = 1 or nx is null
) o on o.CustomerID = c.CustomerID
where c.CustomerStatusID in (1,2)
and c.CustomerTypeID in (2,3);
良好的索引是获得良好性能所必需的。我希望你的表上大致有以下索引，无论是聚集的还是非聚集的（聚集索引 INCLUDE 每隔一列自动），如果需要，你显然可以添加其他 INCLUDE 列：
Customers (CustomerID) INCLUDE (FirstName, LastName)
CustomerTypes (CustomerTypeID) INCLUDE (CustomerTypeDescription)
CustomerStatuses (CustomerStatusID) INCLUDE (CustomerTypeDescription)
PeriodVolumes (CustomerID) INCLUDE (Volume80)
Periods (PeriodTypeID, StartDate, PeriodID) INCLUDE (EndDate) -- can swap Start and End
Orders (CustomerID, OrderDate) INCLUDE (OrderStatusID, SubTotal, Country, BusinessVolumeTotal)
OrderDetails (OrderID, BusinessVolume) INCLUDE (ItemCode ItemDescription)
PriceTypes (PriceTypeID) INCLUDE (PriceTypeDescription)
您应该仔细考虑 INNER 与 LEFT 联接，因为优化器可以更轻松地围绕 INNER 联接移动。
另请注意，DISTINCT 不是函数，它是在整个列集上计算的。通常，可以假设如果 DISTINCT 在查询中，则连接没有被正确考虑。
我需要按订单日期查找每个客户的第一个和最后一个订单，以及每个订单中业务量最高的商品的名称和 SKU。作为参考，Customer table 有超过 150k 条记录，Orders 和 OrderDetails（这些是 Items）更多。
注意：订单及其各自的项目应与客户位于同一行
订单
OrderID OrderDate CustomerID BusinessVolumeTotal Subtotal
13212 '2021-09-06' 512312 500.00 25.60
订单详情
OrderID ItemCode ItemDescription BusinessVolume
13212 'SKW-BS' 'Some item' 450.00
在我的第一个查询中，我试图坚持使用连接而不是子查询，这导致了这个
select distinct(c.CustomerID), c.FirstName + ' ' + c.LastName as Name,
cs.CustomerStatusDescription as Status,
ct.CustomerTypeDescription as Type, pv.Volume80 as G3,
fo.OrderID,fo.OrderDate,fo.SubTotal,fo.Country, fod.ItemCode, fod.ItemDescription, fopt.PriceTypeID,
lo.OrderID,lo.OrderDate,lo.SubTotal,lo.Country, lod.ItemCode, lod.ItemDescription, lopt.PriceTypeID
from Customers c
left join CustomerTypes ct on ct.CustomerTypeID = c.CustomerTypeID
left join CustomerStatuses cs on cs.CustomerStatusID = c.CustomerStatusID
left join PeriodVolumes pv on pv.CustomerID = c.CustomerID
left join Orders fo on fo.CustomerID = c.CustomerID -- First Order
left join Orders lo on lo.CustomerID = c.CustomerID -- Last Order
left join OrderDetails fod on fod.OrderID = fo.OrderID
left join OrderDetails lod on lod.OrderID = lo.OrderID
left join PriceTypes fopt on fo.PriceTypeID = fopt.PriceTypeID
left join PriceTypes lopt on lo.PriceTypeID = lopt.PriceTypeID
where c.CustomerStatusID in (1,2)
and c.CustomerTypeID in (2,3)
and pv.PeriodTypeID = 2
/* First Order */
and fo.OrderID = (select top 1(OrderID) from Orders where CustomerID = c.CustomerID and OrderStatusID>=7 order by OrderDate )
and fod.ItemID = (select top 1(ItemID) from OrderDetails where OrderID = fo.OrderID order by BusinessVolume)
/* Last Order */
and lo.OrderID = (select top 1(OrderID) from Orders where CustomerID = c.CustomerID and OrderStatusID>=7 order by OrderDate desc)
and lod.ItemID = (select top 1(ItemID) from OrderDetails where OrderID = lo.OrderID order by BusinessVolume desc)
and pv.PeriodID = (select PeriodID from Periods where PeriodTypeID=2 and StartDate <= @now and EndDate >= @now)
但这最终执行了大约 6-7 分钟。从解释计划来看，它看起来大部分被基于 OrderStatusID >= 7 的订单键查找占用。
所以我尝试使用 window 函数来实现相同的目的：
select distinct(c.CustomerID), c.FirstName + ' ' + c.LastName as Name, cs.CustomerStatusDescription as Status,
ct.CustomerTypeDescription as Type, pv.Volume80 as G3,
fal.*
from Customers c
left join CustomerTypes ct on ct.CustomerTypeID = c.CustomerTypeID
left join CustomerStatuses cs on cs.CustomerStatusID = c.CustomerStatusID
left join PeriodVolumes pv on pv.CustomerID = c.CustomerID
left join(
select
CustomerID,
max(case when MinDate = 1 then OrderID end) FirstOrderID,
max(case when MinDate = 1 then OrderDate end) FirstOrderDate,
max(case when MinDate = 1 then BusinessVolumeTotal end) FirstBVTotal,
max(case when MinDate = 1 then PriceTypeDescription end) FirstPriceType,
max(case when MinDate = 1 then ItemCode end) FirstItemCode,
max(case when MinDate = 1 then ItemDescription end) FirstItemDescription,
max(case when MaxDate = 1 then OrderID end) LastOrderID,
max(case when MaxDate = 1 then OrderDate end) LastOrderDate,
max(case when MaxDate = 1 then BusinessVolumeTotal end) LastBVTotal,
max(case when MaxDate = 1 then PriceTypeDescription end) LastPriceType,
max(case when MaxDate = 1 then ItemCode end) LastItemCode,
max(case when MaxDate = 1 then ItemDescription end) LastItemDescription
from
(
select distinct o.CustomerID,
o.OrderID,
o.OrderDate,
o.BusinessVolumeTotal,
PT.PriceTypeDescription,
RANK() over (partition by o.CustomerID order by OrderDate) as MinDate,
RANK() over (partition by o.CustomerID order by OrderDate desc) as MaxDate,
FIRST_VALUE(ItemCode) over (partition by od.OrderID order by BusinessVolume desc) as ItemCode,
FIRST_VALUE(ItemDescription) over (partition by od.OrderID order by BusinessVolume desc) as ItemDescription
from Orders o
left join OrderDetails od on od.OrderID = o.OrderID
left join PriceTypes PT on o.PriceTypeID = PT.PriceTypeID
where o.OrderStatusID >= 7
) fal
group by CustomerID
) fal on c.CustomerId = fal.CustomerID
where c.CustomerStatusID in (1,2)
and c.CustomerTypeID in (2,3)
and pv.PeriodTypeID = 2
/* CurrentG3 */
and pv.PeriodID = (select PeriodID from Periods where PeriodTypeID=2 and StartDate <= @now and EndDate >= @now)
唉，这最终执行的时间更长了。如果可能的话，我需要一种优化方法。
二次查询
我还需要过去 3、6 和 12 个月内每个订单的数量和总和。我目前在原始 returns 结果之后以编程方式作为辅助查询执行此操作，并且我转发 CustomerID，如下所示：
select count(OrderID) as Cnt, sum(BusinessVolumeTotal) as Bv, CustomerID
from Orders where OrderStatusID > 6 and OrderTypeID in (1,4,8,11)
and OrderDate >= @timeAgo and CustomerID in @ids group by CustomerID
乘以 3，因为 3、6 和 12 个月。理想情况下，我也想制作原版的这一部分，但我真的不知道如何去做，尤其是订单的加入是多么复杂。
所以理想情况下我会得到这样的结果 table
CustomerID Name CustomerStatus CustomerType FirstOrderID FirstOrderDate FirstBVTotal FirstItemCode FirstItemDesc FirstPriceType LastOrderID LastOrderDate LastBVTotal LastItemCode LastItemDesc LastPriceType ThreeMonthCount ThreeMonthTotal SixMonthCount SixMonthTotal TwelveMonthCount TwelveMonthTotal
512312 'Jane Doe' 'Active' 'Retail' 13212 '2020-06-06' 50.00 'Item1' 'Item 1 desc' 'Retail' 14321 '2021-09-01' 200.00 'Item2' 'Item 2 desc' 'Retail' 45 4305.00 76 8545.60 183 21542.95
任何关于如何优化或减少查询的帮助和建议，以及任何您认为我做错的事情都将不胜感激。
P.S。我不知道这个标题是否合适以及我是否可以稍后更改它，我已经有一段时间没有使用 SO 来问一个问题了。
更新
查询 1 的实际执行计划：
https://www.brentozar.com/pastetheplan/?id=SJd56RSmK
查询 2 的实际执行计划：
https://www.brentozar.com/pastetheplan/?id=BJ7QHk87Y
我认为您需要牢记此类查询的两个要点：
- window 函数获得良好性能的关键是不要引入不必要的排序。因此，虽然您可以使用
ROW_NUMBER获得任一方向的第一个订单，但您不应该使用另一个相反的ROW_NUMBER获得最后一个。而是使用LEAD检查下一行是否存在，从而告诉您这是否是最后一行。然后您可以使用条件聚合。 - 通常有两种计算 first/last 的方法：一种是行编号解决方案，如上所述，另一种是
APPLY，它可以准确地找出您需要的一种。
我认为对于OrderDetails我们应该使用申请，因为我们只需要为每个客户查找两个订单。这确实需要良好的索引，因此如果OrderDetails没有很好的索引，那么您可能也想为此切换到行编号解决方案。
select
c.CustomerID,
c.FirstName + ' ' + c.LastName as Name,
cs.CustomerStatusDescription as Status,
ct.CustomerTypeDescription as Type,
pv.Volume80 as G3,
o.FirstOrderID,
o.FirstOrderDate,
o.FirstSubTotal,
o.FirstCountry,
fod.ItemCode as FirstItemCode,
fod.ItemDescription as FirstItemDescription,
fopt.PriceTypeDescription as FirstPriceTypeDescription,
o.LastOrderID,
o.LastOrderDate,
o.LastSubTotal,
o.LastCountry,
lod.ItemCode as LastItemCode,
lod.ItemDescription as LastItemDescription,
lopt.PriceTypeDescription as LastPriceTypeDescription
from Customers c
left join CustomerTypes ct on ct.CustomerTypeID = c.CustomerTypeID
left join CustomerStatuses cs on cs.CustomerStatusID = c.CustomerStatusID
left join PeriodVolumes pv on pv.CustomerID = c.CustomerID
and pv.PeriodTypeID = 2
and pv.PeriodID = (
select top 1 PeriodID
from Periods p
where p.PeriodTypeID = 2
and p.StartDate <= @now
and p.EndDate >= @now
)
left join (
select
o.CustomerID,
min(case when rn = 1 then OrderID end) as FirstOrderId,
min(case when rn = 1 then OrderDate end) as FirstOrderDate,
min(case when rn = 1 then SubTotal end) as FirstSubTotal,
min(case when rn = 1 then Country end) as FirstCountry,
min(case when nx is null then OrderID end) as LastOrderId,
min(case when nx is null then OrderDate end) as LastOrderDate,
min(case when nx is null then SubTotal end) as LastSubTotal,
min(case when nx is null then Country end) as LastCountry,
count(case when o.OrderDate >= DATEADD(month, -3, GETDATE()) then 1 end) as ThreeMonthCount,
sum(case when o.OrderDate >= DATEADD(month, -3, GETDATE()) then BusinessVolumeTotal end) as ThreeMonthTotal,
count(case when o.OrderDate >= DATEADD(month, -6, GETDATE()) then 1 end) as SixMonthCount,
sum(case when o.OrderDate >= DATEADD(month, -6, GETDATE()) then BusinessVolumeTotal end) as SixMonthTotal,
count(case when o.OrderDate >= DATEADD(month, -12, GETDATE()) then 1 end) as TwelveMonthCount,
sum(case when o.OrderDate >= DATEADD(month, -12, GETDATE()) then BusinessVolumeTotal end) as TwelveMonthTotal
from (
select *,
ROW_NUMBER() over (partition by o.CustomerID order by OrderDate) as rn,
LEAD(OrderID) over (partition by o.CustomerID order by OrderDate) as nx
from Orders o
where o.OrderStatusID >= 7
and o.OrderTypeID in (1,4,8,11)
and o.OrderDate >= @timeAgo
) o
group by o.CustomerID
) o on o.CustomerID = c.CustomerID
outer apply (
select top 1
od.ItemCode,
od.ItemDescription
from OrderDetails od
order by od.BusinessVolume desc
where od.OrderID = o.FirstOrderId
) fod
outer apply (
select top 1
od.ItemCode,
od.ItemDescription
from OrderDetails od
order by od.BusinessVolume desc
where od.OrderID = o.LastOrderId
) lod
left join PriceTypes fopt on fopt.PriceTypeID = o.FirstPriceTypeID
left join PriceTypes lopt on lopt.PriceTypeID = o.LastPriceTypeID
where c.CustomerStatusID in (1,2)
and c.CustomerTypeID in (2,3);
我也给你一个行编号的版本，从你的执行计划来看，它实际上可能更好。你需要两者都试一下
select
c.CustomerID,
c.FirstName + ' ' + c.LastName as Name,
cs.CustomerStatusDescription as Status,
ct.CustomerTypeDescription as Type,
pv.Volume80 as G3,
o.FirstOrderID,
o.FirstOrderDate,
o.FirstSubTotal,
o.FirstCountry,
o.FirstItemCode,
o.FirstItemDescription,
o.FirstPriceTypeDescription,
o.LastOrderID,
o.LastOrderDate,
o.LastSubTotal,
o.LastCountry,
o.LastItemCode,
o.LastItemDescription,
o.LastPriceTypeDescription
from Customers c
left join CustomerTypes ct on ct.CustomerTypeID = c.CustomerTypeID
left join CustomerStatuses cs on cs.CustomerStatusID = c.CustomerStatusID
left join PeriodVolumes pv on pv.CustomerID = c.CustomerID
and pv.PeriodTypeID = 2
and pv.PeriodID = (
select top 1 PeriodID
from Periods p
where p.PeriodTypeID = 2
and p.StartDate <= @now
and p.EndDate >= @now
)
left join (
select
o.CustomerID,
min(case when rn = 1 then o.OrderID end) as FirstOrderId,
min(case when rn = 1 then o.OrderDate end) as FirstOrderDate,
min(case when rn = 1 then o.SubTotal end) as FirstSubTotal,
min(case when rn = 1 then o.Country end) as FirstCountry,
min(case when rn = 1 then od.ItemCode end) as FirstItemCode,
min(case when rn = 1 then od.ItemDescription end) as FirstItemDescription,
min(case when rn = 1 then opt.PriceTypeDescription end) as FirstPriceTypeDescription,
min(case when nx is null then o.OrderID end) as LastOrderId,
min(case when nx is null then o.OrderDate end) as LastOrderDate,
min(case when nx is null then o.SubTotal end) as LastSubTotal,
min(case when nx is null then o.Country end) as LastCountry,
min(case when nx is null then od.ItemCode end) as LastItemCode,
min(case when nx is null then od.ItemDescription end) as LastItemDescription,
min(case when nx is null then opt.PriceTypeDescription end) as LastPriceTypeDescription,
count(case when o.OrderDate >= DATEADD(month, -3, GETDATE()) then 1 end) as ThreeMonthCount,
sum(case when o.OrderDate >= DATEADD(month, -3, GETDATE()) then BusinessVolumeTotal end) as ThreeMonthTotal,
count(case when o.OrderDate >= DATEADD(month, -6, GETDATE()) then 1 end) as SixMonthCount,
sum(case when o.OrderDate >= DATEADD(month, -6, GETDATE()) then BusinessVolumeTotal end) as SixMonthTotal,
count(case when o.OrderDate >= DATEADD(month, -12, GETDATE()) then 1 end) as TwelveMonthCount,
sum(case when o.OrderDate >= DATEADD(month, -12, GETDATE()) then BusinessVolumeTotal end) as TwelveMonthTotal
from (
select *,
ROW_NUMBER() over (partition by o.CustomerID order by OrderDate) as rn,
LEAD(OrderID) over (partition by o.CustomerID order by OrderDate) as nx
from Orders o
where o.OrderStatusID >= 7
and o.OrderTypeID in (1,4,8,11)
and o.OrderDate >= @timeAgo
) o
left join PriceTypes opt on opt.PriceTypeID = o.PriceTypeID
join (
select *,
ROW_NUMBER() over (partition by od.OrderID order by od.BusinessVolume desc) as rn
from OrderDetails od
) od on od.OrderID = o.OrderId
where rn = 1 or nx is null
) o on o.CustomerID = c.CustomerID
where c.CustomerStatusID in (1,2)
and c.CustomerTypeID in (2,3);
良好的索引是获得良好性能所必需的。我希望你的表上大致有以下索引，无论是聚集的还是非聚集的（聚集索引 INCLUDE 每隔一列自动），如果需要，你显然可以添加其他 INCLUDE 列：
Customers (CustomerID) INCLUDE (FirstName, LastName)
CustomerTypes (CustomerTypeID) INCLUDE (CustomerTypeDescription)
CustomerStatuses (CustomerStatusID) INCLUDE (CustomerTypeDescription)
PeriodVolumes (CustomerID) INCLUDE (Volume80)
Periods (PeriodTypeID, StartDate, PeriodID) INCLUDE (EndDate) -- can swap Start and End
Orders (CustomerID, OrderDate) INCLUDE (OrderStatusID, SubTotal, Country, BusinessVolumeTotal)
OrderDetails (OrderID, BusinessVolume) INCLUDE (ItemCode ItemDescription)
PriceTypes (PriceTypeID) INCLUDE (PriceTypeDescription)
您应该仔细考虑 INNER 与 LEFT 联接，因为优化器可以更轻松地围绕 INNER 联接移动。
另请注意，DISTINCT 不是函数，它是在整个列集上计算的。通常，可以假设如果 DISTINCT 在查询中，则连接没有被正确考虑。