一、引言

删除分区又称为合并分区，简单地讲就是将多个分区的数据进行合并。现以表Sales.SalesOrderHeader作为示例，演示如何进行表分区删除？

重要的事情说三遍：备份数据库！备份数据库！备份数据库！

二、演示

2.1、数据查询

1）查看分区元数据

SELECT * FROM SYS.PARTITION_FUNCTIONS       --分区函数
SELECT * FROM SYS.PARTITION_RANGE_VALUES    --分区方案

2）统计每个分区的数据量

SELECT $PARTITION.SalesOrderHeader_OrderDate(OrderDate) AS NUMBER,COUNT(1) AS COUNT
FROM [Sales].[SalesOrderHeader]
GROUP BY $PARTITION.SalesOrderHeader_OrderDate(OrderDate)

分区表中有数据时，是不能够删除分区方案和分区函数的，只能将数据先移到其它表中，再删除。

2.2、删除实操

2.2.1、合并原表分区

ALTER PARTITION FUNCTION SalesOrderHeader_OrderDate() MERGE RANGE('2011-01-01 00:00:00.000')
ALTER PARTITION FUNCTION SalesOrderHeader_OrderDate() MERGE RANGE('2012-01-01 00:00:00.000')
ALTER PARTITION FUNCTION SalesOrderHeader_OrderDate() MERGE RANGE('2013-01-01 00:00:00.000')
ALTER PARTITION FUNCTION SalesOrderHeader_OrderDate() MERGE RANGE('2014-01-01 00:00:00.000')

2.2.2、备份原表所有索引的创建脚本

ALTER TABLE [Sales].[SalesOrderHeader] ADD  CONSTRAINT [PK_SalesOrderHeader_SalesOrderID] PRIMARY KEY NONCLUSTERED 
(
    [SalesOrderID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

2.2.3、删除原表所有索引

ALTER TABLE [Sales].[SalesOrderHeader] DROP CONSTRAINT [PK_SalesOrderHeader_SalesOrderID]

2.2.4、创建临时表

CREATE TABLE [Sales].[SalesOrderHeader_Temp](
    [SalesOrderID] [INT] IDENTITY(1,1) NOT FOR REPLICATION NOT NULL,
    [RevisionNumber] [TINYINT] NOT NULL,
    [OrderDate] [DATETIME] NOT NULL,
    [DueDate] [DATETIME] NOT NULL,
    [ShipDate] [DATETIME] NULL,
    [Status] [TINYINT] NOT NULL,
    [OnlineOrderFlag] [dbo].[Flag] NOT NULL,
    [SalesOrderNumber]  AS (ISNULL(N'SO'+CONVERT([NVARCHAR](23),[SalesOrderID]),N'*** ERROR ***')),
    [PurchaseOrderNumber] [dbo].[OrderNumber] NULL,
    [AccountNumber] [dbo].[AccountNumber] NULL,
    [CustomerID] [INT] NOT NULL,
    [SalesPersonID] [INT] NULL,
    [TerritoryID] [INT] NULL,
    [BillToAddressID] [INT] NOT NULL,
    [ShipToAddressID] [INT] NOT NULL,
    [ShipMethodID] [INT] NOT NULL,
    [CreditCardID] [INT] NULL,
    [CreditCardApprovalCode] [VARCHAR](15) NULL,
    [CurrencyRateID] [INT] NULL,
    [SubTotal] [MONEY] NOT NULL,
    [TaxAmt] [MONEY] NOT NULL,
    [Freight] [MONEY] NOT NULL,
    [TotalDue]  AS (ISNULL(([SubTotal]+[TaxAmt])+[Freight],(0))),
    [Comment] [NVARCHAR](128) NULL,
    [rowguid] [UNIQUEIDENTIFIER] ROWGUIDCOL  NOT NULL,
    [ModifiedDate] [DATETIME] NOT NULL
)

2.2.5、更改原表数据空间类型

1）对着原表Sales.SalesOrderHeader点击"右键"->"设计"。

2）点击菜单栏"视图"->"属性窗口"。

3）将数据空间类型更改为"文件组"，常规数据空间规范默认为"PRIMARY"。

2.2.6、移动原表分区数据到临时表

ALTER TABLE [Sales].[SalesOrderHeader] SWITCH PARTITION 1 TO [Sales].[SalesOrderHeader_Temp] PARTITION 1

2.2.7、创建原表所有索引到临时表

ALTER TABLE [Sales].[SalesOrderHeader_Temp] ADD  CONSTRAINT [PK_SalesOrderHeader_SalesOrderID] PRIMARY KEY NONCLUSTERED 
(
    [SalesOrderID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

2.2.8、删除原表

DROP TABLE Sales.SalesOrderHeader

2.2.9、删除分区方案和分区函数

DROP PARTITION SCHEME SalesOrderHeader_OrderDate
DROP PARTITION FUNCTION SalesOrderHeader_OrderDate

2.2.10重命名表名

EXEC SP_RENAME '[Sales].[SalesOrderHeader_Temp]','SalesOrderHeader'