Entity Framework Join 3 Tables

Entity Framework Join 3 Tables

This is untested, but I believe the syntax should work for a lambda query. As you join more tables with this syntax you have to drill further down into the new objects to reach the values you want to manipulate.

var fullEntries = dbContext.tbl_EntryPoint
    .Join(
        dbContext.tbl_Entry,
        entryPoint => entryPoint.EID,
        entry => entry.EID,
        (entryPoint, entry) => new { entryPoint, entry }
    )
    .Join(
        dbContext.tbl_Title,
        combinedEntry => combinedEntry.entry.TID,
        title => title.TID,
        (combinedEntry, title) => new 
        {
            UID = combinedEntry.entry.OwnerUID,
            TID = combinedEntry.entry.TID,
            EID = combinedEntry.entryPoint.EID,
            Title = title.Title
        }
    )
    .Where(fullEntry => fullEntry.UID == user.UID)
    .Take(10);

How to join 3 tables in entity framework 6

In the second Join clause, the item type is the anonymous type you just created in the previous (first) Join clause. In it the fields are defined as X and Y instead of t1 and t2, so these are the fields you should use.

entities.X
.Join(entities.Y, t1 => t1.ID, t2 => t2.ID1, (t1, t2) => new { X = t1, Y = t2 })
.Join(entities.Z.Where(p => p.param == 1), t2 => t2.Y.ID, t3 => t3.ID2, (t, t3) => new { X = t.X, Z = t3 })
.Select(u => u.X)
.Distinct();

(Edited to reflect the original SQL query, and explanation added)

Note: Where clause may be added at the end as well, but I used the current form because it is usually better to filter first (i.e. before joining, etc.).

How can I join multiple tables including a join-table (auto-generated by Entity Framework) using LINQ

Use the following query:

var query = 
    from exams in _context.Exams
    from students in exams.Class.Students
    join people in _context.People on students.PersonId equals people.Id
    where exams.Id == id
    select new
    {
        Id = students.Id,
        FullName = people.FirstName + " " + people.LastName
    };

How to join 3 tables with linq

Can you try something similar to it please for joining part

from d in Duty
join c in Company on d.CompanyId equals c.id
join s in SewagePlant on c.SewagePlantId equals s.id
select new
  {
      duty = s.Duty.Duty, 
      CatId = s.Company.CompanyName,
      SewagePlantName=s.SewagePlant.SewagePlantName
      // other assignments
  };

How to join multiple tables in entity framework

You can create a custom class to hold only ProductName and IsEnabled like this:

public class ProductEnableInfo
{
    public string ProductName { get; set; }
    public bool IsEnabled { get; set; }
}

Then you can change your method to this:

public IEnumerable<ProductEnableInfo> GetProducts()
{
    return db.Products.Select(
        x => new ProductEnableInfo
        {
            ProductName = x.ProductName,
            IsEnabled = x.ProductDetail.IsEnabled
        })
        .ToList();
}

UPDATE:

You can filter by ProductID like this:

public IEnumerable<ProductEnableInfo> GetProducts(int product_id)
{
    return db.Products
        .Where(x => x.ProductID == product_id)
        .Select(
        x => new ProductEnableInfo
        {
            ProductName = x.ProductName,
            IsEnabled = x.ProductDetail.IsEnabled
        })
        .ToList();
}

Join three tables with Entity Framework

You have navigation properties in your model. That means you don't need to worry about joins - they will be generated for you.

The equivalent LINQ query is simple as that:

var query = from hasta in db.Hasta
            select new
            { 
               hasta.HastaAdSoyad,
               hasta.Randevu.RandevuTarihi,
               hasta.Randevu.RandevuSaati
             };
var result = query.ToList();

It's not clear why the original SQL query includes join to Doktor table.

If you really want joins (for some unknown reason), then the query is

var query = from hasta in db.Hasta
            join randevu in db.Randevu on hasta.RandevuId equals randevu.RandevuId
            join doktor in db.Doktor on randevu.DoktorId equals doktor.DoktorId
            select new
            { 
               hasta.HastaAdSoyad,
               randevu.RandevuTarihi,
               randevu.RandevuSaati
             };

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