LINQ内部联接4个表（将SQL转换为C＃LINQ）

Question

Hello. I am trying to join 4 tables:

tStore(StoreID, Store_Name)

tSection(SectionID, Section_Name)

tSectionSqft(SectionSqftID, StoreID, SectionID,Sqft)

tSectionForwardSelling(SectionForwardSellingID, StoreID, SectionID, Amount, Date)

I want the query to give me results:

Store_Name, Section_Name, Sqft, Amount

I need to convert this SQL query to C# LINQ:

SELECT
    tStore.Store_Name, 
    tSection.Section_Name,  
    tSectionSqft.Sqft,  
    tSectionForwardSelling.Amount
FROM tSection  
INNER JOIN tSectionForwardSelling 
      ON tSection.SectionID = tSectionForwardSelling.SectionID 
INNER JOIN tSectionSqft 
      ON tSection.SectionID = tSectionSqft.SectionID 
INNER JOIN tStore 
      ON tSectionForwardSelling.StoreID = tStore.StoreID 
         AND tSectionSqft.StoreID = tStore.StoreID

I tried on my own but each time LINQ gives me wrong results.

Answer 1

var queryResult = from a in tSection
            join b in tSectionForwardSelling on a.SectionID equals b.SectionID 
            join c in tSectionSqft on a.SectionID equals c.SectionID
            join d in tStore on new { u1 = b.SectionID , u2 = c.SectionID } equals new { u1 = d.SectionID , u2 = d.SectionID }
            select new { d.Store_Name, a.Section_Name, c.Sqft, b.Amount };

Answer 2

You should do something like this (just a snippet):

var result = from s in tSection join  ss in tSectionForwardSelling on s.SectionId equals ss.sectionID
        join sq in tSectionSqft on s.SectonId equals sq.SectionID
        join st in stores on ......
        select new {field1 = s.Field1
                    field2 = sq.FieldName,...}

Answer 3

Try this:

public class RetrieveData
{
    public string StoreName { get; set; }
    public string SectionName { get; set; }
    public int Sqft { get; set; }
    public int Amount { get; set; }
}

public void Method(tStore store)
{
    // Store_Name, Section_Name, Sqft, Amount

    var list = from se in Context.Sections
               join fs in tSectionForwardSelling on se.SectionID equals fs.SectionID 
               join sqft in tSectionSqft on se.SectionID equals sqft.SectionID
               join st in tStore on new { u1 = fs.StoreID , u2 = st.StoreID } equals new { u1 = sqft.StoreID , u2 = st.StoreID }
               select new RetrieveData() {
                   StoreName = st.Store_Name,
                   SectionName = se.Section_Name,
                   Sqft = sqft.Sqft,
                   Amount = fs.Amount };
}

I want to give part credit of the join to @Nazmul.