diff --git a/common/Factory/Model.php b/common/Factory/Model.php
index 58a4d38..f0c819b 100644
--- a/common/Factory/Model.php
+++ b/common/Factory/Model.php
@@ -29,12 +29,17 @@ class Model {
     return $this;
   }
   protected $columns;
+  /**
+   * <column>, [<column1>, <column2>, ...]
+   * string | array(array)
+   * <column>: [<name>, *<alias>, *<type>]
+   */
   public function select($columns): Model {
     if ($this->columns == null) {
       $this->columns = [];
     }
     if (!is_array($columns)) {
-      $columns = [$columns];
+      $columns = [[$columns]];
     }
     $this->columns = array_merge($this->columns, $columns);
     return $this;
@@ -43,12 +48,21 @@ class Model {
     if ($this->columns == null or count($this->columns) == 0) {
       return $orm;
     }
-    foreach ($this->columns as $column => $alias) {
-      if (is_numeric($column)) {
-        $orm = $orm->select($alias);
-        continue;
+    foreach ($this->columns as $column) {
+      if (is_string($column)) {
+        $column = [$column];
       }
-      $orm = $orm->select($column, $alias);
+      $alias = $column['alias'] ?? $column[1] ?? $column[0];
+      $method = 'select';
+      if (count($column) > 2 or isset($column['type'])) {
+        $type = $column['type'] ?? $column[2] ?? '';
+        switch ($type) {
+          case 'expr':
+            $method .= 'Expr';
+            break;
+        }
+      }
+      $orm = $orm->{$method}($column, $alias);
     }
     return $orm;
   }