我是 LINQ 和 Lamda 表达式的新手。我有一个有点复杂的 SQL 语句,它从几个数据库表中检索信息:
SELECT A.OrderID, A.FORMJDENO, A.Title, B.Descr, C.Code, C.Descr, D.ModificationDate from OrderForm A
LEFT JOIN OrderPriority B ON A.OrderPriorityID = B.OrderPriorityID
LEFT JOIN StockClass C ON A.StockClassID = C.StockClassID
LEFT JOIN AuditTrailLog D ON A.OrderID = D.ObjectID
WHERE D.ColumnInfoID= 487 AND D.OldValue='1' AND D.NewValue='2' AND A.FormStatus=2 AND A.FormType=3 AND B.OrderPriorityID=1000001 AND C.StockClassID=1000002
AND A.DeptID IN
( SELECT DeptID FROM Department WHERE InstID = 1000006 )
AND DATEDIFF(m,D.ModificationDate, A.VendorDeliveryDate) >= 3
我已经几乎完成了 LINQ,使用.Contains()
替换WHERE...IN
SQL 子句的方法,但我需要一些帮助来joins
根据属于其他表的值限制结果并DATEDIFF
在 LINQ 中使用等效项。这是我已经得到的并且工作正常,但显然它并没有像上面的 SQL 语句那样限制结果。我尝试了几种方法都没有成功。我需要等效的 LINQ
更新:
最后我能够让它工作。这是检索与 SQL 语句相同的记录的最终 LINQ。非常感谢@Gert Arnold:
var valid = dba.OrderForm
.Where(q => q.FormType == 3
&& q.FormStatus == 2
&& q.OrderPriority.OrderPriorityID == orderpriorityID
&& q.StockClass.StockClassID == stockclassID
&& dba.AuditTrailLog.Where(log => q.OrderID==log.ObjectID)
.Any(log => log.ColumnInfoID == 487
&& log.OldValue == "1"
&& log.NewValue == "2"
&& EntityFunctions.DiffMonths(log.ModificationDate,
q.VendorDeliveryDate) >= period)
&& departments.Contains(q.DeptID));