加入，group by和SQL計數到LINQ轉換

Question

查詢：

SELECT COUNT(*) as Avalied 
FROM LeaveMaster as lm 
JOIN LeaveSubsidary as ls 
ON lm.TransMasterId = ls.TransMasterId 
WHERE lm.SystemCode = 'abc123' AND lm.EmployeeCode = '0014' AND lm.Status ='Approved' 
Group by ls.Leave_Type 

你會如何轉換上面的SQL查詢LINQ？謝謝:)

編輯：

from p in db.PY_LeaveTransactionMasterTAB.AsEnumerable() 
join e in db.PY_LeaveTransactionSubsidaryTAB.AsEnumerable() on p.LV_TransMasterId equals e.LV_TransMasterId into grp 
where p.SystemCode == SysCode && p.EmployeeCode == EmpCode && p.Status == "Approved" 
group grp by e.Leave_Type // This line is invalid Why? 

以上是我到目前爲止已經試過，我爲什麼不能做e.Leave_Type或什麼是做group grp by e.Leave_Type正確的方法是什麼？

Answer 1

你可以試試這個：

(from p in db.PY_LeaveTransactionMasterTAB 
join e in db.PY_LeaveTransactionSubsidaryTAB on p.LV_TransMasterId equals e.LV_TransMasterId 
where p.SystemCode == SysCode && p.EmployeeCode == EmpCode && p.Status == "Approved" 
group new {p,e} by new {e.Leave_Type } into gr 
select new 
{ 
    Leave_Type = gr.Key.Leave_Type , 
    Count = gr.Count() 
}).ToList();