From 0e27b1d89654d781e6f44f25dd9cd2f589318128 Mon Sep 17 00:00:00 2001
From: zzpuser <zzpuser@163.com>
Date: Thu, 4 Aug 2016 10:46:28 +0800
Subject: [PATCH] Update Query.php

---
 library/think/db/Query.php | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/library/think/db/Query.php b/library/think/db/Query.php
index 049afea4..120ef9e5 100644
--- a/library/think/db/Query.php
+++ b/library/think/db/Query.php
@@ -595,8 +595,9 @@ class Query
             if (false === $step) {
                 return true; // 等待下次写入
             }
+            $step = -$step;
         }
-        return $this->setField($field, ['exp', $field . '+' . $step]);
+        return $this->setField($field, ['exp', $field . '-' . $step]);
     }
 
     /**