SQL Server 添加或修改列

－－添加列

IF NOT EXISTS(SELECT * FROM SYSCOLUMNS WHERE id=OBJECT_ID(‘tbl_TranWOAndCoCHistoryByRAILASSURE‘) AND name=‘CreatedDate‘)
BEGIN

ALTER TABLE tbl_TranWOAndCoCHistoryByRAILASSURE
ADD CreatedDate DATETIME NOT NULL DEFAULT GETDATE()

END

－－修改列

IF  EXISTS(SELECT * FROM SYSCOLUMNS WHERE id=OBJECT_ID(‘tbl_TranWOAndCoCHistoryByRAILASSURE‘) AND name=‘CreatedDate‘)
BEGIN

ALTER TABLE tbl_TranWOAndCoCHistoryByRAILASSURE
ALTER COLUMN CreatedDate NVARCHAR(10)

END

－－1.删除列，先删除默认值约束名

IF  EXISTS(SELECT * FROM SYSCOLUMNS WHERE id=OBJECT_ID(‘tbl_TranWOAndCoCHistoryByRAILASSURE‘) AND name=‘CreatedDate‘)
BEGIN

ALTER TABLE tbl_TranWOAndCoCHistoryByRAILASSURE
DROP constraint DF__tbl_TranW__CreatedDate__359DCDD0

END

－－2.删除列

IF  EXISTS(SELECT * FROM SYSCOLUMNS WHERE id=OBJECT_ID(‘tbl_TranWOAndCoCHistoryByRAILASSURE‘) AND name=‘CreatedDate‘)
BEGIN

ALTER TABLE tbl_TranWOAndCoCHistoryByRAILASSURE
DROP COLUMN CreatedDate

END