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如何使用unioan和嵌套的linq?

linq visual-studio-2008 .net c#

loki · 技术社区 · 16 年前

How can i convert to sql to linq . i don't understand nested select query. i need linq codes. Please help me:((((

SELECT @id=id FROM 
    (SELECT id,workorder AS workorderno ,CAST(jobseqno AS int) AS jobseqno FROM dbo.CTask
     UNION ALL
     SELECT id,workorderno,cardno AS jobseqno FROM dbo.NonRoutineCard
     UNION ALL
     SELECT id,workorderno,cardno AS jobseqno FROM dbo.AdditionalWorkCard) a
WHERE RTRIM(workorderno)=RTRIM(@ToNo) AND jobseqno=@ToSeq

LINQ:

  var id = 
  (from task in stock.CTasks select new { task.id, task.workorder, task.jobseqno } )
  .Union(from card in stock.NonRoutineCards select new { card.id, card.workorderno, card.cardno })
  .Union(from card in stock.AdditionalWorkCards select new { card.id, card.workorderno, card.cardno })
  .Where(x => x.workorderno.TrimEnd() == ToNo && x.jobseqno == ToSeq)
  .FirstOrDefault();

如果我写上面的代码,错误如下:

alt text http://i47.tinypic.com/2lax4au.png

1 回复 | 直到 16 年前

torvin Mayank 16 年前

那能满足你的需要吗?

var id = 
  (from task in stock.CTasks select new { task.id, task.workorder, jobseqno= task.jobseqno } )
  .Union(from card in stock.NonRoutineCards select new { card.id, card.workorderno, jobseqno = card.cardno })
  .Union(from card in stock.AdditionalWorkCards select new { card.id, card.workorderno, jobseqno = card.cardno })
  .Where(x => x.workorderno.TrimEnd() == ToNo && x.jobseqno == ToSeq)
  .FirstOrDefault();

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