查詢中的第四行當前回傳多個“RitsId”。我想通過添加以下兩個條件從中選擇一個“RitsId”。
需要按“日期”和“點數”過濾
- 其中 'points' 不等于 10（其中 rits.Points != 10）
- 通過 rits 表中的最新“日期”查詢回傳單個記錄（例如：.OrderByDescending(rits => rits.RitsDate)
我可以知道如何在以下查詢中添加這些條件嗎？我還是個初學者。謝謝你。
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;
型號如下：
目標是從 tableOT 中獲取“描述”，以便傳入“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; }
}
uj5u.com熱心網友回復：
嘗試以下查詢：
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();
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標籤：林克 实体框架核心 asp.net-core-webapi