修复Filter::between无效bug

src/Grid/Filter/Between.php

@@ -37,13 +37,14 @@ class Between extends AbstractFilter
      */
     protected function formatName($column)
     {
-        $gridName = $this->parent->getGrid()->getName().'_';
+        $gridName = $this->parent->getGrid()->getName();
+        $prefix = $gridName ? $gridName.'_' : '';
         $columns = explode('.', $column);
 
         if (count($columns) == 1) {
-            $name = $gridName.$columns[0];
+            $name = $prefix.$columns[0];
         } else {
-            $name =  $gridName.array_shift($columns);
+            $name =  $prefix.array_shift($columns);
 
             foreach ($columns as $column) {
                 $name .= "[$column]";