From 513f1f32f7561b4ecce69ddf574f3cf4872479bd Mon Sep 17 00:00:00 2001
From: thinkphp <thinkphp@qq.com>
Date: Tue, 9 May 2017 15:38:41 +0800
Subject: [PATCH] =?UTF-8?q?=E6=94=B9=E8=BF=9Bbelongstomany=E7=9A=84?=
 =?UTF-8?q?=E6=9F=A5=E8=AF=A2=E5=AD=97=E6=AE=B5=E6=8C=87=E5=AE=9A?=
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---
 library/think/model/Relation.php              | 26 +++++++++++++++++++
 .../think/model/relation/BelongsToMany.php    |  4 ++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/library/think/model/Relation.php b/library/think/model/Relation.php
index 81b496ad..4869e526 100644
--- a/library/think/model/Relation.php
+++ b/library/think/model/Relation.php
@@ -77,6 +77,32 @@ abstract class Relation
         return (new $this->model)->toCollection($resultSet);
     }
 
+    protected function getQueryFields($model)
+    {
+        $fields = $this->query->getOptions('field');
+        return $this->getRelationQueryFields($fields, $model);
+    }
+
+    protected function getRelationQueryFields($fields, $model)
+    {
+        if ($fields) {
+
+            if (is_string($fields)) {
+                $fields = explode(',', $fields);
+            }
+
+            foreach ($fields as &$field) {
+                if (false === strpos($field, '.')) {
+                    $field = $model . '.' . $field;
+                }
+            }
+        } else {
+            $fields = $model . '.*';
+        }
+
+        return $fields;
+    }
+
     /**
      * 执行基础查询（仅执行一次）
      * @access protected
diff --git a/library/think/model/relation/BelongsToMany.php b/library/think/model/relation/BelongsToMany.php
index 79684fe7..9eeb88dd 100644
--- a/library/think/model/relation/BelongsToMany.php
+++ b/library/think/model/relation/BelongsToMany.php
@@ -376,7 +376,9 @@ class BelongsToMany extends Relation
         // 关联查询封装
         $tableName = $this->query->getTable();
         $table     = $this->pivot->getTable();
-        $query     = $this->query->field($tableName . '.*')
+        $fields    = $this->getQueryFields($tableName);
+
+        $query = $this->query->field($fields)
             ->field(true, false, $table, 'pivot', 'pivot__');
 
         if (empty($this->baseQuery)) {