From 006b45dd9ae8359357e5a15e355d2577f1df3a75 Mon Sep 17 00:00:00 2001
From: thinkphp <thinkphp@qq.com>
Date: Wed, 27 Apr 2016 17:35:49 +0800
Subject: [PATCH] =?UTF-8?q?=E6=94=B9=E8=BF=9Bquery=E7=B1=BB=E7=9A=84?=
 =?UTF-8?q?=E8=81=9A=E5=90=88=E6=9F=A5=E8=AF=A2=E6=96=B9=E6=B3=95=E7=9A=84?=
 =?UTF-8?q?=E8=BF=94=E5=9B=9E=E5=80=BC?=
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---
 library/think/db/Query.php | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/library/think/db/Query.php b/library/think/db/Query.php
index 5c399d49..a9ba0a5d 100644
--- a/library/think/db/Query.php
+++ b/library/think/db/Query.php
@@ -179,7 +179,8 @@ class Query
      */
     public function sum($field = '*')
     {
-        return $this->value('SUM(' . $field . ') AS tp_sum');
+        $result = $this->value('SUM(' . $field . ') AS tp_sum');
+        return is_null($result) ? 0 : $result;
     }
 
     /**
@@ -190,7 +191,8 @@ class Query
      */
     public function min($field = '*')
     {
-        return $this->value('MIN(' . $field . ') AS tp_min');
+        $result = $this->value('MIN(' . $field . ') AS tp_min');
+        return is_null($result) ? 0 : $result;
     }
 
     /**
@@ -201,7 +203,8 @@ class Query
      */
     public function max($field = '*')
     {
-        return $this->value('MAX(' . $field . ') AS tp_max');
+        $result = $this->value('MAX(' . $field . ') AS tp_max');
+        return is_null($result) ? 0 : $result;
     }
 
     /**
@@ -212,7 +215,8 @@ class Query
      */
     public function avg($field = '*')
     {
-        return $this->value('AVG(' . $field . ') AS tp_avg');
+        $result = $this->value('AVG(' . $field . ') AS tp_avg');
+        return is_null($result) ? 0 : $result;
     }
 
     /**