csharp Linq加入多个可空列

Posted 2021-05-12

from t in _policyPrintingNoteRepository.GetAll()
join p in _planRepository.GetAll() on new { t.PlanCode, t.ProductId } 
  equals new { PlanCode = p.Code, p.ProductId } into planView from p in planView.DefaultIfEmpty()
join pr in _productRepository.GetAll() on t.ProductId 
  equals pr.Id into productView from pr in productView.DefaultIfEmpty()
orderby t.Id descending
select
    new
    {
        t.Id,
        t.StartDate,
        t.EndDate,
        t.ProductId,
        ProductName = pr.Id + " " + pr.Name,
        t.PlanCode,
        PlanName = t.PlanCode + " " + p.Name,
        t.ProposalStatus,
        t.NoteTypeCode,
    };