Question

我正在尝试构建一个按Name和Year排序的查询，过滤具有更高年份的重复项并将这些记录返回到表中。我的数据目前看起来像这样：

ID-----Name-----Year
1      Bob      2010
2      John     2014
3      Bob      2004
4      Eric     2005

数据应主要按Name排序，然后按Year按降序排序，如下所示：

ID-----Name-----Year
3      Bob      2004
1      Bob      2010
4      Eric     2005
2      John     2014

然后重复的Name条记录应该过滤，只返回最低Year，如下所示：

ID-----Name-----Year
3      Bob      2004
4      Eric     2005
2      John     2014

我尝试了SELECT DISTINCT和HAVING COUNT之类的内容，但似乎无法得到它。可能缺少一些简单的东西。有什么帮助吗？

Answer 1

select ID, Name, Year
from (
    select ID, Name, Year, Rank() over (partition by Name order by year) as Rank
    from MyTable
) t
where Rank = 1

SQL FIddle Example #1

如果您无法使用PARTITION，则可以执行此操作：

select m.ID, m.Name, m.Year
from (
    select Name, min(Year) as MinYear
    from MyTable
    group by Name
) mm
inner join MyTable m on mm.Name = m.Name and mm.MinYear = m.Year

SQL Fiddle Example #2

Answer 2

SELECT Name, MIN(Year) FROM table
GROUP BY Name
ORDER BY Name ASC

Answer 3

假设MySQL

select min(id), name, min(year)
from (
select distinct t1.id, t1.name, t2.year
from tbl t1, tbl t2
odrer by t1.name, t2.year
) T
group by name

SQL返回非重复记录

3 个答案: