LEFT JOIN in LINQ to entities?

by

Ah, got it myselfs.
The quirks and quarks of LINQ-2-entities.
This looks most understandable:

var query2 = (
    from users in Repo.T_Benutzer
    from mappings in Repo.T_Benutzer_Benutzergruppen
        .Where(mapping => mapping.BEBG_BE == users.BE_ID).DefaultIfEmpty()
    from groups in Repo.T_Benutzergruppen
        .Where(gruppe => gruppe.ID == mappings.BEBG_BG).DefaultIfEmpty()
    //where users.BE_Name.Contains(keyword)
    // //|| mappings.BEBG_BE.Equals(666)  
    //|| mappings.BEBG_BE == 666 
    //|| groups.Name.Contains(keyword)

    select new
    {
         UserId = users.BE_ID
        ,UserName = users.BE_User
        ,UserGroupId = mappings.BEBG_BG
        ,GroupName = groups.Name
    }

);


var xy = (query2).ToList();

Remove the .DefaultIfEmpty(), and you get an inner join.
That was what I was looking for.

More Related Contents:

  1. Dynamic where clause (OR) in Linq to Entities
  2. How to create LINQ Expression Tree to select an anonymous type
  3. ‘Contains()’ workaround using Linq to Entities?
  4. “A lambda expression with a statement body cannot be converted to an expression tree”
  5. Bulk-deleting in LINQ to Entities
  6. The type of one of the expressions in the join clause is incorrect in Entity Framework
  7. Entity framework left join
  8. Entity Framework/Linq EXpression converting from string to int
  9. How to compare only date components from DateTime in EF?
  10. The result of a query cannot be enumerated more than once
  11. “The LINQ expression node type ‘Invoke’ is not supported in LINQ to Entities” – stumped!
  12. Linq to Entity Join table with multiple OR conditions
  13. Creating dynamic queries with entity framework
  14. ‘Date’ is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported
  15. Dynamic query with OR conditions in Entity Framework
  16. Calling a SQL User-defined function in a LINQ query
  17. The LINQ expression node type ‘ArrayIndex’ is not supported in LINQ to Entities
  18. LINQ to Entities group-by failure using .date
  19. How do I apply OrderBy on an IQueryable using a string column name within a generic extension method?
  20. How to do a Bulk Insert — Linq to Entities
  21. Entity-framework code is slow when using Include() many times
  22. The operation cannot be completed because the DbContext has been disposed using MVC 4
  23. Export Model to DataTable
  24. EF4 Code First: how to add a relationship without adding a navigation property
  25. Entity Framework 4: How to find the primary key?
  26. Max return value if empty query
  27. Check if list contains item from other list in EntityFramework
  28. Add the where clause dynamically in Entity Framework
  29. Keep Getting ‘The LINQ expression node type ‘Invoke’ is not supported in LINQ to Entities’ Exception
  30. Repository Pattern, POCO, and Business Entities

Leave a Comment