sqlserver巧用row_number和partition by分组取top数据

语法形式：ROW_NUMBER() OVER(PARTITION BY COL1 ORDER BY COL2)

解释：根据COL1分组，在分组内部根据 COL2排序，而此函数计算的值就表示每组内部排序后的顺序编号（组内连续的唯一的)

select * from
(
select subject,name,score,ROW_NUMBER() over(PARTITION by subject order by score desc) as num from #score
) T where T.num <= 3 order by subject

高级用法