50.修改标识的案例

--测试资料
CREATE TABLE t1(ID int IDENTITY,A int)
INSERT t1 VALUES(1)
INSERT t1 VALUES(2)
INSERT t1 VALUES(3)
DELETE FROM t1 WHERE A=2
GO

--将ID=3的记录的ID值改为2
SET IDENTITY_INSERT t1 ON
INSERT t1(ID,A) SELECT 2,A FROM t1 WHERE ID=3
DELETE FROM t1 WHERE ID=3
SET IDENTITY_INSERT t1 OFF
SELECT * FROM t1
/*--结果
ID          A 
----------------- ----------- 
1           1
2           3
--*/