在LINQ中操作 [英] IN operation in LINQ

问题描述

你好。我想在LINQ中写这个t-sql

 选择 * 来自 [Ticket] t 其中 t.TicketStatusId   
（
 选择 k.TicketStatusId 来自 [TreeOfKnowledgeData] k 
）

请帮助我。

解决方案

IN = 在Linq中包含



http://www.dotnetperls.com/list-contains [ ^ ]



但是，你的SQL查询显然看起来像这样



http://stackoverflow.com/questions/25355004/simple -exampl e-subquery-linq [ ^ ]



我希望这会对你有所帮助：）

想一想！您不需要使用 IN ，您必须使用加入 [ ^ ]！为什么？很明显：上面的语句只获得 TicketStatusId 字段等于 TreeOfKnowledgeDataTicketStatusId 的票证。

  var  qry = 来自票据 票证
 加入 knowdata   TickO上的TreeOfKnowledgeDatas.TicketStatusId等于knowdata.TicketStatusId 
 选择票证; 

如果您想从两个表格中获取数据，请尝试以下方法：

  var  qry = 来自 ticket  门票
 加入 knowdata  在ticket.TicketStatusId上的TreeOfKnowledgeDatas等于knowdata.TicketStatu sdd 
 选择  new  
 {
 statid = ticket.TicketStatusId， 
 kbd = knowdata.AnotherField 
}; 

Hi . I want to write this t-sql in LINQ

select * from [Ticket] t where t.TicketStatusId in
(
    select k.TicketStatusId  from [TreeOfKnowledgeData] k
)

please help me .

解决方案

IN = Contains in Linq

http://www.dotnetperls.com/list-contains[^]

but, your sql query is obviously look like this

http://stackoverflow.com/questions/25355004/simple-example-subquery-linq[^]

I hope this will help you :)

Think of it! You don't need to use IN, you have to use Join[^]! Why? It's quite obvious: above statement get only that tickets which TicketStatusId field is equal to TreeOfKnowledgeDataTicketStatusId.

var qry = from ticket in Tickets 
     join knowdata in TreeOfKnowledgeDatas on ticket.TicketStatusId equals knowdata.TicketStatusId
    select ticket;

If you would like to get data from both "tables", try this:

var qry = from ticket in Tickets 
     join knowdata in TreeOfKnowledgeDatas on ticket.TicketStatusId equals knowdata.TicketStatusId
    select new
    {
         statid = ticket.TicketStatusId, 
         kbd    = knowdata.AnotherField
    };

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