需要幫助將SQL左連接查詢轉換爲LINQ格式

Question

我是LINQ的新手，但語法尚不完善。有人可以幫助我將這個SQL查詢轉換爲一個LINQ語句，供我的C＃項目使用。

SELECT g.GalleryTitle, m.* 
FROM Media AS m LEFT JOIN Galleries AS g ON m.GalleryID = g.GalleryID 
WHERE m.MediaDate >= GETDATE() - 30 
ORDER BY m.Views DESC 

Answer 1

from m in Db.Media 
join g in Db.Galleries on m.GalleryID equals g.GalleryID into MediaGalleries 
from mg in MediaGalleries.DefaultIfEmpty() 
where m.MediaDate >= DateTime.Today.AddDays(-30) 
orderby m.Views descending 
select new 
{ 
    GalleryTitle = mg != null ? mg.GalleryTitle : null, 
    Media = m 
}; 

Answer 2

我不能現在就測試它，但它應該是這樣的：

var result = Media.GroupJoin(Galleries, m => m.GalleryID, g => g.GalleryID, 
        (m, g) => new {m, g}) 
        .SelectMany(mg => mg.g.DefaultIfEmpty(), 
        (m,g) => new { Media = m.m, GalleryTitle = g != null ? g.GalleryTitle : default(string) }) 
        .OrderByDescending(m => m.Media.Views).ToList(); 

Answer 3

var result = from m in Media 

      join g in Galleries 
       on m.GalleryId equals g.GalleryId 
      into gJoinData 
      from gJoinRecord in gJoinData.DefaultIfEmpty() 

      where m.MediaDate.CompareTo(DateTime.Today.AddDays(-30.0)) >= 0 
      orderby m.Views descending 

      select new 
      { 
       M_Record = m, 
       GalleryTitle = gJoinRecord.GalleryTitle 
      };