Question

我想将以下SQL语句翻译成linq查询：

select COUNT(*), itemid,  globalid, title, preview, previewimage, previewimage_alt, link  
from (
        select distinct Id, itemid,  globalid, title, preview, previewimage, previewimage_alt,
               (select top 1 link from LikeCounter where GlobalId=x.GlobalId) as link
        from [LikeCounter] x
        where PortalId=1 and LanguageId=1
    ) as t
GROUP BY itemid, globalid, title, preview, previewimage, previewimage_alt, link
ORDER BY COUNT(*) desc

查询位于一个视图上，该视图保存“喜欢”对象的记录。由于对象可以在多个位置发布，并且视图设置为允许对特定位置进行过滤，因此在对记录进行分组之前需要一个不同的内容来查找视图计数（这是“链接”的附加查询的原因“专栏”。

在一个linq语句中是否可以嵌套SELECT语句？

内部查询没问题：

(from x in LikeCounter
where x.PortalId==1 && x.LanguageId==1  
select new {x.Id, x.ItemId, x.GlobalId, x.LanguageId, x.Title, x.Preview, x.PreviewImage_alt, 
              Morelink=(from y in LikeCounter
              where y.GlobalId==x.GlobalId
              select y.Morelink).FirstOrDefault()
           }).Distinct()

但是有没有办法通过对不同记录进行分组来扩展它，这会导致只对数据库进行一次查询？

提前感谢任何输入......

尼娜

编辑：

以下查询几乎返回我想要的内容 - 但会向SQL服务器生成多个查询：

(from y in 
((from x in LikeCounter
where x.PortalId==1 && x.LanguageId==1 
select new {x.Id, x.ItemId, x.GlobalId, x.LanguageId, x.Title, x.Preview, x.PreviewImage_alt, 
              Link=(from y in Xparo_LikeCounter
              where y.GlobalId==x.GlobalId
              select y.Link).FirstOrDefault()
           }).Distinct())
group y by y.GlobalId into grp
select new {Data=grp, Count= grp.Count()}).OrderByDescending (x => x.Count)

Answer 1

我认为以下应该可行，但我无法真正测试它。不知道它需要多少次查询

from subq in (from x in LikeCounter
              where x.PortalId==1 && x.LanguageId==1  
              select new {x.Id, x.ItemId, x.GlobalId, x.LanguageId, x.Title, x.Preview, x.PreviewImage_alt, 
              Morelink=(from y in LikeCounter
              where y.GlobalId==x.GlobalId
              select y.Morelink).FirstOrDefault()
              }).Distinct()
group subq by new {TheCount = subq.Id.Count(), subq.Id, subq.ItemId, subq.GlobalId, subq.LanguageId, subq.Title, subq.Preview, subq.PreviewImage_alt, subq.Morelink } into grouped
order by grouped.TheCount descending;

Linq查询具有分组和不同的嵌套select语句

1 个答案: