如何在 linq 查询中编写非重复数和计数
本文关键字:linq 查询 | 更新日期: 2023-09-27 18:37:26
我有一个 SQL,我正在尝试将其转换为 c# 中的 Linq 表达式。
你能帮忙吗?
if (String.IsNullOrEmpty(alpha))
sql = "select distinct(Keyword) as word,
count(*) as Counter
from Keywords
group by keyword
order by keyword desc";
else
sql = "select distinct(Keyword) as word,
count(*) as Counter
from Keywords
where starts = N'{0}'
group by keyword
order by keyword desc";
我知道我在同一个查询中有不同和计数,没有好方法可以弄清楚如何做到这一点?如何为此编写 LinQ 表达式?
int? startFilter = 10;
var test1 = items.Where(i => startFilter.HasValue == false || i.Starts == startFilter.Value)
.GroupBy(i => i.Keyword).Select(grp => new { Keyword = grp.Key, Count = grp.Count()})
.ToList();
您可以将其分为三个部分:
IEnumerable<Keyword> query = db.Keywords;
if(String.IsNullOrEmpty(alpha))
query = query.Where(k => k.starts == alpha)
// need to change from Keyword collection to anonymous type collection
var query2 = query.GroupBy(k => k.Keyword)
.Select(g => new {
word = g.Key,
Counter = g.Count()
}
);