if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[T_TestTable]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
if ( NOT exists ( select * from dbo.syscolumns where name = ' sum ' and id in
( select id from dbo.sysobjects where id = object_id (N ' [dbo].[T_TestTable] ' ) and OBJECTPROPERTY (id, N ' IsUserTable ' ) = 1 ))
)
ALTER TABLE [ dbo ] . [ T_TestTable ] ADD sum float
GO
if ( NOT exists ( select * from dbo.syscolumns where name = ' sum ' and id in
( select id from dbo.sysobjects where id = object_id (N ' [dbo].[T_TestTable] ' ) and OBJECTPROPERTY (id, N ' IsUserTable ' ) = 1 ))
)
ALTER TABLE [ dbo ] . [ T_TestTable ] ADD sum float
GO