diff --git a/sql/sql_string.cc b/sql/sql_string.cc
index 0e62b5b9c2e..94f2e6fc8c6 100644
--- a/sql/sql_string.cc
+++ b/sql/sql_string.cc
@@ -767,10 +767,10 @@ void Static_binary_string::qs_append(double d)
                        NULL);
 }
 
-void Static_binary_string::qs_append(double *d)
+void Static_binary_string::qs_append(const double *d)
 {
   double ld;
-  float8get(ld, (char*) d);
+  float8get(ld, (const char*) d);
   qs_append(ld);
 }
 
diff --git a/sql/sql_string.h b/sql/sql_string.h
index 2ef817ea0ad..d1378e62a97 100644
--- a/sql/sql_string.h
+++ b/sql/sql_string.h
@@ -345,7 +345,7 @@ public:
   void qs_append(const char *str, size_t len);
   void qs_append_hex(const char *str, uint32 len);
   void qs_append(double d);
-  void qs_append(double *d);
+  void qs_append(const double *d);
   inline void qs_append(const char c)
   {
      Ptr[str_length]= c;