订单管理，省市区三个字段可以指定搜索该字段条件是“空”的

app/Services/OrderService.php

@@ -96,13 +96,16 @@ class OrderService
             $sql .= " AND (c_tel2 like '".$c_tel2."' OR c_tel1 like '".$c_tel2."')";
         }
         if ($c_province){
-            $sql .= " AND c_province like '".$c_province."'";
+            if ($c_province=='空')$sql .= " AND c_province is null";
+            else$sql .= " AND c_province like '".$c_province."'";
         }
         if ($c_city){
-            $sql .= " AND c_city like '".$c_city."'";
+            if ($c_city=='空')$sql .= " AND c_city is null";
+            else$sql .= " AND c_city like '".$c_city."'";
         }
         if ($c_district){
-            $sql .= " AND c_district like '".$c_district."'";
+            if ($c_district=='空')$sql .= " AND c_district is null";
+            else$sql .= " AND c_district like '".$c_district."'";
         }
         if ($releasestatus){
             $sql .= " AND releasestatus = '".$releasestatus."'";