Question

好的，这很奇怪，我将尽力解释我的意思。

比方说，我知道目前的sku库存：

select sku, sum(stock)
from stock
where sku = '1234'
group by sku

然后我得到该sku的销售额：

select * 
from sales
where sku = '1234' and saleDate > SOME_DATE   <---- Get sales for a certain period
order by saleDate desc

我想查找什么是库存水平，以及导致库存下降到给定日期的原因。

所以结果应该像这样：

Current stock @ 21.06.2019 is 50     <---- I know this value

20.06.2019: stockStart = 53, sold = 3, stockEnd = 50   <---- I know the sales, don't know the stock
19.06.2019: stockStart = 58, sold = 5, stockEnd = 53   <---- I know the sales, don't know the stock
18.06.2019: stockStart = 60, sold = 2, stockEnd = 58   <---- I know the sales, don't know the stock
17.06.2019: stockStart = 68, sold = 8, stockEnd = 60   <---- I know the sales, don't know the stock

Initial stock @ 16.06.2019 was 68    <---- Don't know this value

如何通过SQL查询获得类似的信息，我知道当前库存，知道出售了什么，但是我想找到：

每个销售行的库存。
最终库存。（这实际上是最后一行，stockStart列）

Answer 1

检查以下查询。某些内联和子查询可能会导致性能问题。但是考虑到您的要求，我认为以下查询将至少为您提供一些指导。

DECLARE @FromDate DATE = '20190619'

SELECT  saleDate Date,
Current_Stock + ISNULL(sold_from_today,0) stockStart,
Sold,
Current_Stock + ISNULL(sold_from_tomorrow,0) stockEnd 
FROM
(
    Select *,
    (select sku, sum(stock) from stock where sku = '1234') Current_Stock,
    --68 Current_Stock,
    (SELECT SUM(Sold) FROM sales B WHERE B.saleDate >= A.saleDate AND  B.saleDate  > @FromDate  AND B.sku = '1234') sold_from_tomorrow,
    (SELECT SUM(Sold) FROM sales B WHERE B.saleDate > A.saleDate AND  B.saleDate  > @FromDate AND B.sku = '1234') Usold_from_today
    from sales A
    where A.sku = '1234' and A.saleDate > @FromDate
)A
ORDER BY saleDate DESC

SQL：如何通过了解当前值来查找初始值以及每一行的值？

1 个答案: