实体框架 Select 与许多表一对多

Question

With the three tables below:

Relationship:

1. Author is one-to-one with AuthorBiography
2. Author is one-to-many with AuthorPrix

and I would perform a query using method syntax in EF Core and Select to limit the fields to return.

SELECT a.FirstName, a.LastName, ab.Biography, ap.PrixName
FROM dbo.Author AS a
LEFT JOIN dbo.AuthorBiography AS ab ON a.AuthorId = ab.AuthorRef
LEFT JOIN dbo.AuthorPrix AS ap ON a.AuthorId = ap.AuthorRef

I can do like that:

var a = dbCtx.Author
                .Include(b => b.AuthorBiography)
                .Include(c => c.AuthorPrixes)
                .Select(a => new { a.FirstName, a.LastName, a.AuthorBiography.Biography })
                .ToList();

But I cannot add the field [Prix Name] to the select. Is still possible using a simple Select or I should use a Join?

Thanks in advance for your help.

Answer 1

You can add SelectMany to your linq query like this:

var a = dbCtx.Author
        .Include(b => b.AuthorBiography)
        .Include(c => c.AuthorPrixes)
        .SelectMany(a => a.AuthorPrixes)
        .Select(a => new { a.PrixName, a.Author.FirstName, a.Author.LastName, a.Author.AuthorBiography.Biography })
                .ToList();