增加关联统计功能

library/think/model/relation/MorphMany.php

@@ -116,6 +116,29 @@ class MorphMany extends Relation
         }
     }
 
+    /**
+     * 关联统计
+     * @access public
+     * @param Model     $result 数据对象
+     * @param \Closure  $closure 闭包
+     * @return integer
+     */
+    public function relationCount($result, $closure)
+    {
+        $morphType = $this->morphType;
+        $morphKey  = $this->morphKey;
+        $type      = $this->type;
+        $pk        = $result->getPk();
+        $count     = 0;
+        if (isset($result->$pk)) {
+            if ($closure) {
+                call_user_func_array($closure, [ & $this->query]);
+            }
+            $count = $this->query->where([$morphKey => $result->$pk, $morphType => $type])->count();
+        }
+        return $count;
+    }
+
     /**
      * 多态一对多 关联模型预查询
      * @access public