[SQL Server 2005]在记录集中增加行号

SQL Server 2005引入了ROW_NUMBER()函数。通过该函数，可以在记录集中方便的增加行号。
以下为在MSDN的解释：
ROW_NUMBER (Transact-SQL)
Updated: 17 July 2006
Returns the sequential number of a row within a partition of a result set, starting at 1 for the first row in each partition.


Syntax

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 syntax of PARTITION BY, 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


Note:

The ORDER BY in the OVER clause orders ROW_NUMBER. If you add an ORDER BY clause to the SELECT statement that orders by a column(s) other than 'Row Number' the result set will be ordered by the outer ORDER BY.

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



Copy Code

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
INNER JOIN Person.Contact c
ON s.SalesPersonID = c.ContactID
INNER JOIN Person.Address a
ON a.AddressID = c.ContactID
WHERE TerritoryID IS NOT NULL
AND SalesYTD <> 0;

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



Copy Code

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;

The following example shows using the PARTITION BY argument.



Copy Code

USE AdventureWorks;
GO
SELECT c.FirstName, c.LastName
,ROW_NUMBER() OVER
(PARTITION BY PostalCode ORDER BY SalesYTD DESC) AS 'Row Number'
,s.SalesYTD, a.PostalCode
FROM Sales.SalesPerson s
INNER JOIN Person.Contact c
ON s.SalesPersonID = c.ContactID
INNER JOIN Person.Address a
ON a.AddressID = c.ContactID
WHERE TerritoryID IS NOT NULL
AND SalesYTD <> 0;