sql ROW_NUMBER 用法

转自：http://msdn.microsoft.com/en-us/library/ms186734.aspx

SQL Server 2008 R2

Returns the sequential number of a row within a partition of a result set, starting at 1 for the first row in each partition.

sql ROW_NUMBER 用法 Transact-SQL Syntax Conventions

Syntax

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ROW_NUMBER ()     OVER ( [ <partition_by_clause> ] <order_by_clause> )

Arguments

<partition_by_clause>

Divides the result set produced by the FROM clause into partitions to which the ROW_NUMBER function is applied. For the PARTITION BY syntax, see OVER Clause (Transact-SQL).

<order_by_clause>

Determines the order in which the ROW_NUMBER value is assigned to the rows in a partition. For more information, see ORDER BY Clause (Transact-SQL). An integer cannot represent a column when the <order_by_clause> is used in a ranking function.

Return Types

bigint

Remarks

The ORDER BY clause determines the sequence in which the rows are assigned their unique ROW_NUMBER within a specified partition.

Examples

A. Returning the row number for salespeople

The following example returns the ROW_NUMBER for the salespeople in AdventureWorks2008R2 based on the year-to-date sales.

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SELECT FirstName, LastName, ROW_NUMBER() OVER(ORDER BY SalesYTD DESC) AS 'Row Number', SalesYTD, PostalCode 

FROM Sales.vSalesPerson

WHERE TerritoryName IS NOT NULL AND SalesYTD <> 0;

B. Returning a subset of rows

The following example returns rows with numbers 50 to 60 inclusive in the order of the OrderDate.

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USE AdventureWorks2008R2;
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;

C. Using ROW_NUMBER() with PARTITION

The following example shows using the ROW_NUMBER function with the PARTITION BY argument.

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SELECT FirstName, LastName, ROW_NUMBER() OVER(PARTITION BY PostalCode ORDER BY SalesYTD DESC) AS 'Row Number', SalesYTD, PostalCode 
FROM Sales.vSalesPerson
WHERE TerritoryName IS NOT NULL AND SalesYTD <> 0;

Reference

RANK (Transact-SQL)

DENSE_RANK (Transact-SQL)

NTILE (Transact-SQL)

Ranking Functions (Transact-SQL)

Built-in Functions (Transact-SQL)