1 select avg(col) from (select top 3 col from tb order by datetime desc) as t 2 select top 3 * from (select top 6 * from tb order by datetime desc) as t order by col 3 select * from tb where datediff(month,datetime,getdate())=12
1.获得字段的平均值,即离当前时间最近的前三条记录(即三次平均) avg() top 2.获字段离当前时间最近的前六条记录中的最高值(即三次最高) top order by 3.获取去年同一个月份的字段值(即去年同期)dateadd(yy,-1,datecol)
select avg(col) from (select top 3 col from tb order by datetime desc) as t
2
select top 3 * from (select top 6 * from tb order by datetime desc) as t order by col
3
select * from tb where datediff(month,datetime,getdate())=12
2.获字段离当前时间最近的前六条记录中的最高值(即三次最高) top
order by 3.获取去年同一个月份的字段值(即去年同期)dateadd(yy,-1,datecol)