增加关联统计功能

library/think/Model.php

@@ -1308,6 +1308,29 @@ abstract class Model implements \JsonSerializable, \ArrayAccess
         }
     }
 
+    /**
+     * 关联统计
+     * @access public
+     * @param Model             $result 数据对象
+     * @param string|array      $relation 关联名
+     * @return void
+     */
+    public function relationCount(&$result, $relation)
+    {
+        $relations = is_string($relation) ? explode(',', $relation) : $relation;
+
+        foreach ($relations as $key => $relation) {
+            $closure = false;
+            if ($relation instanceof \Closure) {
+                $closure  = $relation;
+                $relation = $key;
+            }
+            $relation = Loader::parseName($relation, 1, false);
+            $count    = $this->$relation()->relationCount($result, $closure);
+            $result->setAttr(Loader::parseName($relation) . '_count', $count);
+        }
+    }
+
     /**
      * HAS ONE 关联定义
      * @access public

library/think/db/Query.php

@@ -1666,6 +1666,18 @@ class Query
         return $this;
     }
 
+    /**
+     * 关联统计
+     * @access public
+     * @param string|array    $relation 关联方法名
+     * @return $this
+     */
+    public function withCount($relation)
+    {
+        $this->options['with_count'] = $relation;
+        return $this;
+    }
+
     /**
      * 关联预加载中 获取关联指定字段值
      * example:
@@ -1997,6 +2009,10 @@ class Query
                     if (!empty($options['relation'])) {
                         $result->relationQuery($options['relation']);
                     }
+                    // 关联统计
+                    if (!empty($options['with_count'])) {
+                        $result->relationCount($result, $options['with_count']);
+                    }
                     $resultSet[$key] = $result;
                 }
                 if (!empty($options['with'])) {
@@ -2095,10 +2111,14 @@ class Query
                 if (!empty($options['relation'])) {
                     $data->relationQuery($options['relation']);
                 }
+                // 预载入查询
                 if (!empty($options['with'])) {
-                    // 预载入
                     $data->eagerlyResult($data, $options['with'], is_object($result) ? get_class($result) : '');
                 }
+                // 关联统计
+                if (!empty($options['with_count'])) {
+                    $data->relationCount($data, $options['with_count']);
+                }
             }
         } elseif (!empty($options['fail'])) {
             $this->throwNotFound($options);

library/think/model/relation/BelongsToMany.php

@@ -145,6 +145,26 @@ class BelongsToMany 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)
+    {
+        $localKey   = $this->localKey;
+        $foreignKey = $this->foreignKey;
+        $pk         = $result->getPk();
+        $count      = 0;
+        if (isset($result->$pk)) {
+            $pk    = $result->$pk;
+            $count = $this->belongsToManyQuery($this->middle, $foreignKey, $localKey, ['pivot.' . $localKey => $pk])->count();
+        }
+        return $count;
+    }
+
     /**
      * 多对多 关联模型预查询
      * @access public

library/think/model/relation/HasMany.php

@@ -113,6 +113,27 @@ class HasMany 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)
+    {
+        $localKey   = $this->localKey;
+        $foreignKey = $this->foreignKey;
+        $count      = 0;
+        if (isset($result->$localKey)) {
+            if ($closure) {
+                call_user_func_array($closure, [ & $this->query]);
+            }
+            $count = $this->query->where([$foreignKey => $result->$localKey])->count();
+        }
+        return $count;
+    }
+
     /**
      * 一对多 关联模型预查询
      * @access public

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