利用 distinct 关键字过滤重复的行,将查询的结果写入临时表
select distinct * into #temp from mytable
删除原表的数据
delete mytable
将临时表插入到表中
insert mytable select * from #temp
释放临时表
drop table #temp
删除数据行是NULL的
delete from mytable where time is null
update table set [coulms]='new-values' where [coulms]='values' and year(备份时间)=2019 and Month(备份时间)=11 and DAY(备份时间)=13