Question

我在sql中遇到问题，假设我有一个主表“项目”，它的项目包括2个不同的细节，如项目成员，项目文件。现在的情况是，项目可能包含10个成员和4个文件，即对应一个项目ID。

我如何从三个表中获取数据并在UI中显示。

var qry = (from p in dbModel.tbl_PROJECT
           join q in dbModel.tbl_PROJECTxFILE
           on p.ProjectID equals q.ProjectID
           into list2

           from l2 in list2.DefaultIfEmpty()
           join f in dbModel.tbl_FILE
           on l2.FileID equals f.FileID
           into list3

           from l3 in list3.DefaultIfEmpty()
            join c in dbModel.tbl_PROJECTxCOMPONENT
           on p.ProjectID equals c.ProjectID
            into list8

           from l8 in list8.DefaultIfEmpty()
           join a in dbModel.tbl_PROJECTCOMPONENT
           on l8.ProjectComponentID equals a.ProjectComponentID
            into list9

           from l9 in list9.DefaultIfEmpty()
           where p.ProjectID == projectId
           select new ProjectDetails1
           {

               ProjectTtile = p.ProjectTtile,
               ProjectIcon = p.ProjectIcon,
               ProjectDescription = p.ProjectDescription,
               ExpectedDeadline = p.ExpectedDeadline,
               FileName = l3.FileName,
               FilePath = l3.FilePath,
               FileSize = l3.FileSize,
               UploadDate = l3.UploadDate,
               FileID = l3.FileID,
               Title = l9.Title,
               ColorId = l9.ColorID,
               ProjectComponentID=l9.ProjectComponentID,
           }).ToList();

Answer 1

您是否尝试过滤特定行？然后你需要使用Offset和Fetch子句，例如....你首先指定OFFSET子句，指示你想要跳过多少行（如果你不想跳过任何行，则为0）;然后，您可以选择指定FETCH子句，指示要过滤的行数，希望这会有所帮助。谢谢

使用sql从多个表中获取数据

1 个答案: