常用的sql语句
1.往一个表中添加新的一列并添加默认值
alter table ClassToCourse add StuYear int not null default 0 with values;
2. 查询分组后的多余的一条数据
select * from ChargeStardSet where id in (select max(id) from ChargeStardSet group by ChargeItemId,StuAttendSchool,OgId having count(*) > 1)