diff --git a/sql/field.h b/sql/field.h
index c64d6bc..57fd25f 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -2488,10 +2488,37 @@ class Field_blob :public Field_longstr {
   int cmp_binary(const uchar *a,const uchar *b, uint32 max_length=~0L);
   int key_cmp(const uchar *,const uchar*);
   int key_cmp(const uchar *str, uint length);
-  /* Never update the value of min_val for a blob field */
-  bool update_min(Field *min_val, bool force_update) { return FALSE; }
-  /* Never update the value of max_val for a blob field */
-  bool update_max(Field *max_val, bool force_update) { return FALSE; }
+  bool update_min(Field *min_val, bool force_update) {
+    bool update_fl;
+    uchar *min_ptr,*blob;
+    uint32 min_len = MY_MIN(((Field_blob *) min_val)->get_length(), 255);
+    uint32 len = MY_MIN(get_length(), 255);
+    ((Field_blob *) min_val)->get_ptr(&min_ptr);
+    get_ptr(&blob);
+    update_fl= force_update || cmp(blob, len, min_ptr, min_len) < 0;
+    if (update_fl)
+    {
+      min_val->set_notnull();
+      min_val->store((const char *)blob, len, charset());
+    }
+    return update_fl;
+  }
+  bool update_max(Field *max_val, bool force_update)
+  {
+    bool update_fl;
+    uchar *max_ptr,*blob;
+    uint32 max_len = MY_MIN(((Field_blob *) max_val)->get_length(), 255);
+    uint32 len = MY_MIN(get_length(), 255);
+    ((Field_blob *) max_val)->get_ptr(&max_ptr);
+    get_ptr(&blob);
+    update_fl= force_update || cmp(blob, len, max_ptr, max_len) > 0;
+    if (update_fl)
+    {
+      max_val->set_notnull();
+      max_val->store((const char *)blob, len, charset());
+    }
+    return update_fl;
+  }
   uint32 key_length() const { return 0; }
   void sort_string(uchar *buff,uint length);
   uint32 pack_length() const