mssqlserver分区表的左值与右值

参考官方文档：

https://docs.microsoft.com/zh-cn/sql/t-sql/statements/create-partition-function-transact-sql

默认是Left

LEFT：第一个值属于第一个表，对应<=

RIGTH: 第一个值属于第二个表，对应<

如果数据按年进行分区，则RIGHT选项且每年的1月1日是合适的。如：

CREATE PARTITION FUNCTION [myDateRangePF1] (datetime)  
AS RANGE RIGHT FOR VALUES ('20030101', '20040101');  
这个有三个区：[0，20030101), [20030101, 20040101), [20040101, 999909999)

Examples

A. Creating a RANGE LEFT partition function on an int column

The following partition function will partition a table or index into four partitions.

tsql

CREATE PARTITION FUNCTION myRangePF1 (int)  
AS RANGE LEFT FOR VALUES (1, 100, 1000);  

The following table shows how a table that uses this partition function on partitioning column col1 would be partitioned.

Partition	1	2	3	4
Values	col1 <= 1	col1 > 1 AND col1 <= 100	col1 > 100 AND col1 <=1000	col1 > 1000

B. Creating a RANGE RIGHT partition function on an int column

The following partition function uses the same values for boundary_value [ ,...n ] as the previous example, except it specifies RANGE RIGHT.

tsql

CREATE PARTITION FUNCTION myRangePF2 (int)  
AS RANGE RIGHT FOR VALUES (1, 100, 1000);  

The following table shows how a table that uses this partition function on partitioning column col1 would be partitioned.

Partition	1	2	3	4
Values	col1 < 1	col1 >= 1 AND col1 < 100	col1 >= 100 AND col1 < 1000	col1 >= 1000

C. Creating a RANGE RIGHT partition function on a datetime column

The following partition function partitions a table or index into 12 partitions, one for each month of a year's worth of values in a datetime column.

tsql

CREATE PARTITION FUNCTION [myDateRangePF1] (datetime)  
AS RANGE RIGHT FOR VALUES ('20030201', '20030301', '20030401',  
               '20030501', '20030601', '20030701', '20030801',   
               '20030901', '20031001', '20031101', '20031201');  

The following table shows how a table or index that uses this partition function on partitioning column datecol would be partitioned.

Partition	1	2	...	11	12
Values	datecol < February 1, 2003	datecol >= February 1, 2003 AND datecol < March 1, 2003		datecol >= November 1, 2003 AND col1 < December 1, 2003	datecol >= December 1, 2003