采购单的平均数 有不止一个单，才算平均数

AutoTurnOver.Services/PurchaseAverageTargetServices.cs

@@ -52,8 +52,8 @@ namespace AutoTurnOver.Services
                     // 查询相关采购单
                     var purchaseList = AveragePurchase.GetPurchaseList(skuItem, _seed_count).ToList();
 
-                    //有相关采购单
-                    if (purchaseList != null && purchaseList.Count() >= 1)
+                    //有相关采购单 (有不止一个单，才算平均数)
+                    if (purchaseList != null && purchaseList.Select(s=>s.purchase_id).Distinct().Count() > 1)
                     {
                         data.supplier_name = purchaseList[0].supplier_name;