Question

I’m working with two tables: CI_CLIENTRISK (SCD type 2)… and QB_INVOICES_HEADER (edmx screenshot).

They can be joined via ClientID. I want to essentially replicate this query:

SELECT a.ClientID,
    MAX(b.InvoiceDt) AS MaxInvoiceDt
    (omitted for brevity)
FROM CI_CLIENTRISKADJS a
INNER JOIN QB_INVOICES_HEADER b
ON a.ClientID = b.ClientID
WHERE a.IsActive = 1
GROUP BY a.ClientID
ORDER BY MaxInvoiceDt DESC

Here’s what I have so far. It’s not returning any records.

using (var db = new PLOGITENS01Entities())
        {
        var rvClientRiskAdjs = db.CI_CLIENTRISKADJS
            .Take(50)
            .Join(db.QB_INVOICES_HEADER,
                a => a.ClientID,
                b => b.ClientID,
                (a, b) => new { Risk = a, Invoices = b })
            .Where(a => a.Risk.IsActive == 1)
            .OrderByDescending(o => o.Invoices.InvoiceDt)
            .Select(c => new ClientRiskModel()
            {
                ClientRiskId = c.Risk.ClientRiskID,
                ClientName = c.Risk.CI_CLIENTLIST.ClientName,
                ClientId = c.Risk.ClientID,
                ClientRiskAdjs = c.Risk.ClientRiskAdjs,
                RecordValidStartDt = c.Risk.RecordValidStartDt,
                RecordValidEnddt = c.Risk.RecordValidEnddt,
                IsActive = c.Risk.IsActive
            })
            .ToList();

        return View(new GridModel(rvClientRiskAdjs));
        }

Answer 1

I stumbled across this solution from reading this post: https://stackoverflow.com/a/157919/1689144

var rvClientRiskAdjs = (from ri in db.CI_CLIENTRISKADJS
                        join qb in
                            (from qb in db.QB_INVOICES_HEADER
                             orderby qb.InvoiceDt ascending
                             group qb by qb.ClientID into grp
                             select new
                             {
                                 InvoiceDt = grp.Max(s => s.InvoiceDt),
                                 ClientID = grp.Key
                             })
                        on ri.ClientID equals qb.ClientID
                        orderby qb.InvoiceDt descending
                        where ri.IsActive == 1
                        select new ClientRiskModel()
                        {
                            ClientRiskId = ri.ClientRiskID,
                            ClientName = ri.CI_CLIENTLIST.ClientName,
                            ClientId = ri.ClientID,
                            ClientRiskAdjs = ri.ClientRiskAdjs,
                            RecordValidEnddt = ri.RecordValidEnddt,
                            RecordValidStartDt = ri.RecordValidStartDt
                        })
                        .ToList();