在Linq to Sql中求和和減法

Question

大家好我想實現類似Linq to Sql的SQL Select語句。任何幫助將不勝感激。

SELECT SUM(Debit-Credit) AS LBalance FROM dbo.LeaveLedger 
WHERE StaffId =1 AND LYEAR='2000' 

Answer 1

假設實體框架：

Context.Table.Where(x => x.StaffId == 1 and x.LYEAR == "2000") 
    .Sum(y => (y.Debit - y.Credit)); 

Answer 2

像這樣的事情？

var sum = 
    db.LeaveLedger 
     .Where(ll => ll.StaffId == 1 and ll.LYEAR == "2000") 
     .Sum(ll => (ll.Debit - ll.Credit)) 

Answer 3

由於曼斯菲爾德已經顯示的表達式語法，我會和經典的查詢一展身手：

var LBalance = (from p in dbo.LeaveLedger 
       where p.StaffId == 1 && p.LYEAR == "2000" 
       select (p.Debit - p.Credit).Sum();