数据表：BUS_VisitorStatics
1、开窗函数实现：
SELECT *
FROM ( SELECT * ,
ROW_NUMBER() OVER ( PARTITION BY visitorDate ORDER BY Count DESC ) AS ‘num‘
FROM BUS_VisitorStatics
) AS tb1
WHERE tb1.num <= 10
2、Linq实现：
DbContext dd = new SZAdminEntities();
list = dd.Set<BUS_VisitorStatics>().OrderByDescending(p => p.Count).ToList();
var result = from n in list
group n by n.VisitorDate
into g
orderby g.Key
select new
{
date = g.Key,
dateList = g.OrderByDescending(p => p.Count).Take(10),
};
var wordlist = new List<BUS_VisitorStatics>();
foreach (var item in result)
{
if (item.dateList.Count() > 0)
{
foreach (var o in item.dateList)
{
var mod = new BUS_VisitorStatics();
mod.VisitorDate = item.date;
mod.Count = o.Count;
mod.Keyword = o.Keyword;
wordlist.Add(mod);
}
}
}
return wordlist;
3、普通SQL实现：
SELECT *
FROM BUS_VisitorStatics AS a
WHERE ( SELECT COUNT(*)
FROM BUS_VisitorStatics AS b
WHERE a.VisitorDate = b.VisitorDate
AND a.Count < b.Count
) < 10
ORDER BY a.VisitorDate ,a.Count DESC