ROW_NUMBER、RANK、DENSE_RANK的用法
(愛新覺羅.毓華? 2007-12-16? 廣東深圳)

SQL Server 2005 引入幾個(gè)新的排序(排名)函數(shù),如ROW_NUMBER、RANK、DENSE_RANK等。
這些新函數(shù)使您可以有效地分析數(shù)據(jù)以及向查詢的結(jié)果行提供排序值。

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ROW_NUMBER()

說明：返回結(jié)果集分區(qū)內(nèi)行的序列號(hào)，每個(gè)分區(qū)的第一行從 1 開始。
語法：ROW_NUMBER () OVER ( [ ] ) 。
備注：ORDER BY 子句可確定在特定分區(qū)中為行分配唯一 ROW_NUMBER 的順序。
參數(shù)： ：將 FROM 子句生成的結(jié)果集劃入應(yīng)用了 ROW_NUMBER 函數(shù)的分區(qū)。
????? ：確定將 ROW_NUMBER 值分配給分區(qū)中的行的順序。
返回類型：bigint 。

示例：
/*以下示例將根據(jù)年初至今的銷售額，返回 AdventureWorks 中銷售人員的 ROW_NUMBER。*/

USE AdventureWorks
GO
SELECT c.FirstName, c.LastName, ROW_NUMBER() OVER(ORDER BY SalesYTD DESC) AS 'Row Number', s.SalesYTD, a.PostalCode
FROM Sales.SalesPerson s JOIN Person.Contact c on s.SalesPersonID = c.ContactID
JOIN Person.Address a ON a.AddressID = c.ContactID
WHERE TerritoryID IS NOT NULL AND SalesYTD <> 0
/*
FirstName? LastName??? Row Number? SalesYTD????? PostalCode
---------? ----------? ----------? ------------? ----------------------------
Shelley??? Dyck??????? 1?????????? 5200475.2313? 98027
Gail?????? Erickson??? 2?????????? 5015682.3752? 98055
Maciej???? Dusza?????? 3?????????? 4557045.0459? 98027
Linda????? Ecoffey???? 4?????????? 3857163.6332? 98027
Mark?????? Erickson??? 5?????????? 3827950.238?? 98055
Terry????? Eminhizer?? 6?????????? 3587378.4257? 98055
Michael??? Emanuel???? 7?????????? 3189356.2465? 98055
Jauna????? Elson?????? 8?????????? 3018725.4858? 98055
Carol????? Elliott???? 9?????????? 2811012.7151? 98027
Janeth???? Esteves???? 10????????? 2241204.0424? 98055
Martha???? Espinoza??? 11????????? 1931620.1835? 98055
Carla????? Eldridge??? 12????????? 1764938.9859? 98027
Twanna???? Evans?????? 13????????? 1758385.926?? 98055
(13 行受影響)
*/

/*以下示例將返回行號(hào)為 50 到 60（含）的行，并以 OrderDate 排序。*/
USE AdventureWorks;
GO
WITH OrderedOrders AS
(SELECT SalesOrderID, OrderDate,
ROW_NUMBER() OVER (order by OrderDate)as RowNumber
FROM Sales.SalesOrderHeader )
SELECT *
FROM OrderedOrders
WHERE RowNumber between 50 and 60;
/*
SalesOrderID OrderDate?????????????? RowNumber
------------ ----------------------- --------------------
43708??????? 2001-07-03 00:00:00.000 50
43709??????? 2001-07-03 00:00:00.000 51
43710??????? 2001-07-03 00:00:00.000 52
43711??????? 2001-07-04 00:00:00.000 53
43712??????? 2001-07-04 00:00:00.000 54
43713??????? 2001-07-05 00:00:00.000 55
43714??????? 2001-07-05 00:00:00.000 56
43715??????? 2001-07-05 00:00:00.000 57
43716??????? 2001-07-05 00:00:00.000 58
43717??????? 2001-07-05 00:00:00.000 59
43718??????? 2001-07-06 00:00:00.000 60
(11 行受影響)
*/

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RANK()

說明：返回結(jié)果集的分區(qū)內(nèi)每行的排名。行的排名是相關(guān)行之前的排名數(shù)加一。
語法：RANK () OVER ( [ < partition_by_clause > ] < order_by_clause > )
備注：如果兩個(gè)或多個(gè)行與一個(gè)排名關(guān)聯(lián)，則每個(gè)關(guān)聯(lián)行將得到相同的排名。
????? 例如，如果兩位頂尖銷售員具有同樣的 SalesYTD 值，他們將并列第一。
????? 由于已有兩行排名在前，所以具有下一個(gè)最大 SalesYTD 的銷售人員將排名第三。
????? 因此，RANK 函數(shù)并不總返回連續(xù)整數(shù)。
????? 用于整個(gè)查詢的排序順序決定了行在結(jié)果集中的顯示順序。這也隱含了行在每個(gè)分區(qū)中的排名。
參數(shù)：< partition_by_clause > ：將 FROM 子句生成的結(jié)果集劃分為要應(yīng)用 RANK 函數(shù)的分區(qū)。
????? < order_by_clause >：確定將 RANK 值應(yīng)用于分區(qū)中的行時(shí)所基于的順序。
返回類型：bigint

示例：
/*以下示例按照數(shù)量對(duì)清單中的產(chǎn)品進(jìn)行了排名。行集按 LocationID 分區(qū)，按 Quantity 排序。
USE AdventureWorks;
GO
SELECT i.ProductID, p.Name, i.LocationID, i.Quantity, RANK() OVER (PARTITION BY i.LocationID order by i.Quantity) as RANK
FROM Production.ProductInventory i JOIN Production.Product p
ON i.ProductID = p.ProductID
ORDER BY p.Name
GO
/*
ProductID?? Name?????????????????????????????????????????????? LocationID Quantity RANK
----------- -------------------------------------------------- ---------- -------- --------------------
1?????????? Adjustable Race??????????????????????????????????? 6????????? 324????? 71
1?????????? Adjustable Race??????????????????????????????????? 1????????? 408????? 78
1?????????? Adjustable Race??????????????????????????????????? 50???????? 353????? 117
2?????????? Bearing Ball?????????????????????????????????????? 6????????? 318????? 67
2?????????? Bearing Ball?????????????????????????????????????? 1????????? 427????? 85
2?????????? Bearing Ball?????????????????????????????????????? 50???????? 364????? 122
3?????????? BB Ball Bearing??????????????????????????????????? 50???????? 324????? 106
3?????????? BB Ball Bearing??????????????????????????????????? 1????????? 585????? 110
3?????????? BB Ball Bearing??????????????????????????????????? 6????????? 443????? 115
4?????????? Headset Ball Bearings????????????????????????????? 1????????? 512????? 99
4?????????? Headset Ball Bearings????????????????????????????? 6????????? 422????? 108
4?????????? Headset Ball Bearings????????????????????????????? 50???????? 388????? 140
316???????? Blade????????????????????????????????????????????? 10???????? 388????? 33
......
(1069 行受影響)
*/

ROW_NUMBER、RANK、DENSE_RANK的用法