diff --git a/src/protocol/MySQLResult.inl b/src/protocol/MySQLResult.inl
index 2a66ffa7..24a01f10 100644
--- a/src/protocol/MySQLResult.inl
+++ b/src/protocol/MySQLResult.inl
@@ -16,6 +16,7 @@
   Authors: Li Yingxin (liyingxin@sogou-inc.com)
 */
 
+#include <math.h>
 #include <string>
 #include <utility>
 #include "mysql_byteorder.h"
@@ -189,7 +190,7 @@ inline bool MySQLCell::is_float() const
 inline float MySQLCell::as_float() const
 {
 	if (!this->is_float())
-		return 0;
+		return NAN;
 
 	char num[MYSQL_FLOAT_STR_LENGTH + 1];
 	memcpy(num, this->data, this->len);
@@ -205,7 +206,7 @@ inline bool MySQLCell::is_double() const
 inline double MySQLCell::as_double() const
 {
 	if (!this->is_double())
-		return 0;
+		return NAN;
 
 	char num[MYSQL_DOUBLE_STR_LENGTH + 1];
 	memcpy(num, this->data, this->len);
@@ -221,7 +222,7 @@ inline bool MySQLCell::is_ulonglong() const
 inline unsigned long long MySQLCell::as_ulonglong() const
 {
 	if (!this->is_ulonglong())
-		return 0;
+		return (unsigned long long)-1;
 
 	char num[MYSQL_LONG_STR_LENGTH + 1];
 	memcpy(num, this->data, this->len);