改进Model类的has和hasWhere方法

library/think/model/relation/BelongsTo.php

@@ -51,6 +51,45 @@ class BelongsTo extends OneToOne
         return $this->query->where($this->localKey, $this->parent->$foreignKey)->relation($subRelation)->find();
     }
 
+    /**
+     * 根据关联条件查询当前模型
+     * @access public
+     * @param string  $operator 比较操作符
+     * @param integer $count    个数
+     * @param string  $id       关联表的统计字段
+     * @param string  $joinType JOIN类型
+     * @return Query
+     */
+    public function has($operator = '>=', $count = 1, $id = '*')
+    {
+        return $this->parent;
+    }
+
+    /**
+     * 根据关联条件查询当前模型
+     * @access public
+     * @param mixed $where 查询条件（数组或者闭包）
+     * @return Query
+     */
+    public function hasWhere($where = [])
+    {
+        $table    = $this->query->getTable();
+        $model    = basename(str_replace('\\', '/', get_class($this->parent)));
+        $relation = basename(str_replace('\\', '/', $this->model));
+        if (is_array($where)) {
+            foreach ($where as $key => $val) {
+                if (false === strpos($key, '.')) {
+                    $where[$relation . '.' . $key] = $val;
+                    unset($where[$key]);
+                }
+            }
+        }
+        return $this->parent->db()->alias($model)
+            ->field($model . '.*')
+            ->join($table . ' ' . $relation, $model . '.' . $this->foreignKey . '=' . $relation . '.' . $this->localKey, $this->joinType)
+            ->where($where);
+    }
+
     /**
      * 预载入关联查询（数据集）
      * @access public