从本质上讲,自动增量是按照增量的数量在每次插入时进行的。
MS SQL Server提供了一种创建反向顺序的方法。看看这里
create table #test
(
TestId INT IDENTITY (2, -1),
DateTimeStamp DateTime
)
GO
INSERT INTO #test (DateTimeStamp) Values (GETDATE());
INSERT INTO #test (DateTimeStamp) Values (GETDATE());
INSERT INTO #test (DateTimeStamp) Values (GETDATE());
INSERT INTO #test (DateTimeStamp) Values (GETDATE());
INSERT INTO #test (DateTimeStamp) Values (GETDATE());
INSERT INTO #test (DateTimeStamp) Values (GETDATE());
INSERT INTO #test (DateTimeStamp) Values (GETDATE());
INSERT INTO #test (DateTimeStamp) Values (GETDATE());
GO
SELECT * FROM #test
结果:
TestId DateTimeStamp
2 2009-07-28 15:02:09.200
1 2009-07-28 15:02:09.200
0 2009-07-28 15:02:09.200
-1 2009-07-28 15:02:09.200
-2 2009-07-28 15:02:09.203
-3 2009-07-28 15:02:09.203
-4 2009-07-28 15:02:09.203
-5 2009-07-28 15:02:09.207