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Linq to Entities: Left join to get elements not found in the join

I have two unrelated (not FK defined) tables. The first table contains some tasks for which the user may not have access. I need to find all these tasks - in this case the joined table will contain zeros. How do I get them?

Here's the setting:

TimeData table 
- userID 
- taskID 
- hours

      

        
        
        
      

    


ApprovedTasks table (the one that should contain nulls)
- taskID 
- userID

The SQL query will look like this:

select * from TimeData td 
left join ApprovedTasks at
 on at.taskID = td.taskID and at.userID = td.userID
where at.taskID is null

Any way to pull this off with a LINQ to Entity query?

TIA

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1 answer


Check out ... Disjoint Union in LINQ

This should work ...



var approvedTaks = from at in ApprovedTasks.Except(
                                        from at2 in ApprovedTasks
                                        where at2.userID == userId and at2.taskID==taskId
                                        select at2)
                    where at.userID == userId and at.taskID==taskId
                    select at;

but sorry, there is no database convenient to check it.

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