执行SQL脚本语句判断是否已经存在
1.字段是否存在
if((select count(*) from syscolumns where name = '字段名' and id=(select id from sysobjects where name='表名'))=0)
begin
end
2.表是否存在
if exists (select * from sysobjects where id = OBJECT_ID('表名') and OBJECTPROPERTY(id, 'IsUserTable') = 1)
DROP TABLE 表名
