[英]How to compare last record and last record - 1?
Lets say I have a table from join select like this: 假设我有一个来自连接的表选择如下:
No.Transaction Item Name PRICE
TC0001 Book 15
TC0001 Pencil 2
TC0001 Eraser 1
TC0002 Book 12
TC0002 Eraser 1.5
TC0003 Pencil 1.8
TC0003 Book 20
I want to compare last price and its previous price for same item name. 我想比较相同商品名称的最后价格和之前的价格。 For example
Book is 20 and 12
, Pencil is 1.8 and 2
例如
Book is 20 and 12
, Pencil is 1.8 and 2
How can I do that? 我怎样才能做到这一点?
I think you need a query like this: 我认为你需要这样的查询:
;WITH t AS (
SELECT *
, ROW_NUMBER() OVER (PARTITION BY [Item Name]
ORDER BY [No.Transaction] DESC) As seq
FROM yourTable)
SELECT t1.[Item Name]
, t1.PRICE As lastPrice
, t2.PRICE As preLastPrice
, t1.PRICE - ISNULL(t2.PRICE, 0) As changePrice
FROM t t1
LEFT JOIN
t t2 ON t1.[Item Name] = t2.[Item Name] AND t1.seq = t2.seq - 1
WHERE (t1.seq = 1);
you must find column for order your result then use DENSE_RANK()
and get 2 last row like this 您必须找到用于订购结果的列,然后使用
DENSE_RANK()
并获得最后一行,如下所示
SELECT *
(
SELECT transactionId
,itm_name
,price
,DENSE_RANK() OVER (PARTITION BY itm_name ORDER BY created_date DESC) AS [rank]
FROM tbl
) res
WHERE res.[rank] IN (1,2)
ORDER BY res.[rank]
Query manipulation. 查询操作。 Adding group by, limit(2), order DESC .
添加group by,limit(2),命令DESC。 you should get what you needed.
你应该得到你需要的东西。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.