加入的附加条件

Question

查询中的第四行当前 return 多个 'RitsId'。我想从中 select 一个 'RitsId'，通过添加以下两个条件。

需要按 'date' 和 'points'

过滤

其中 'points' 不等于 10（其中 rits.Points != 10）
从 rits table return 单条记录按最新 'date' 查询（例如：.OrderByDescending(rits => rits.RitsDate)

我可以知道如何在下面的查询中添加这些条件吗？我还是个初学者。谢谢。

  var query = from ot in DbContext.tableOT
              join rp in DbContext.tableRP on ot.OTId equals rp.OTId 
              join rits in DbContext.tableRITS on rp.RitsId equals rits.RitsId  
  // I get multiple RitsId as result in the below line, should add conditions to get a single RitsId of my choice
              join ri in DbContext.tableRI on rits.RId equals ri.RId 
              where ri.ItemNo == itemno

            select new pt()
                          {
                              ...
                          }).FirstOrDefaultAsync(); 

        
 return await query;

型号如下：

目标是从 tableOT 获得 'Description' 用于传入 'ItemNo'。

 public partial class tableRI 
{
    public string ItemNo { get; set; }
    public Guid RId { get; set; }

}  

// I get multiple 'RitsId' for passed in 'RID', Need to add conditions to get single 'RitsId'
 public partial class tableRITS 
{
    public Guid RitsId { get; set; } 
    public Guid RId { get; set; }
    public DateTime RitsDate{ get; set; }
    public int? Points { get; set; }
}

 // By adding conditions, I can retrieve and pass the single RitsId of my choice below
 public partial class tableRP 
{
    public Guid RitsId { get; set; }
    public Guid? OTId { get; set; }

}

public partial class tableOT
{
    public Guid? OTId { get; set; }
    public string Description { get; set; }

}

Answer 1

尝试以下查询：

var query = 
    from ri in DbContext.tableRI
    where ri.ItemNo == itemno
    from rits in DbContext.tableRITS
      .Where(rits => rits.Points != 10 && ri.RId == rits.RId)
      .OrderByDescending(rits => RitsDate)
      .Take(1)
    join rp in DbContext.tableRP on rits.RitsId equals r.RitsId 
    join ot in DbContext.tableOT on rits.OTId equals ot.OTId 
    select new 
    {
        // ... maybe other properties
        ot.Description
    };

return await query.FirstOrDefaultAsync();

加入的附加条件

Additional conditions to join

linq

entity-framework-core

asp.net-core-webapi