diff --git a/mysql-test/r/func_str.result b/mysql-test/r/func_str.result
index ae60daef0ac..5335f53d382 100644
--- a/mysql-test/r/func_str.result
+++ b/mysql-test/r/func_str.result
@@ -876,3 +876,6 @@ abc	abc	c	bc	abc
 abcd	abcd	d	cd	bcd	abcd	
 abcde	abcde	e	de	cde	bcde	abcde
 drop table t1;
+select hex(29223372036854775809), hex(-29223372036854775809);
+hex(29223372036854775809)	hex(-29223372036854775809)
+FFFFFFFFFFFFFFFF	FFFFFFFFFFFFFFFF
diff --git a/mysql-test/r/rpl_deadlock.result b/mysql-test/r/rpl_deadlock.result
index 866edb45cbb..b112a51a145 100644
--- a/mysql-test/r/rpl_deadlock.result
+++ b/mysql-test/r/rpl_deadlock.result
@@ -84,4 +84,4 @@ a
 show slave status;
 Slave_IO_State	Master_Host	Master_User	Master_Port	Connect_Retry	Master_Log_File	Read_Master_Log_Pos	Relay_Log_File	Relay_Log_Pos	Relay_Master_Log_File	Slave_IO_Running	Slave_SQL_Running	Replicate_Do_DB	Replicate_Ignore_DB	Replicate_Do_Table	Replicate_Ignore_Table	Replicate_Wild_Do_Table	Replicate_Wild_Ignore_Table	Last_Errno	Last_Error	Skip_Counter	Exec_Master_Log_Pos	Relay_Log_Space	Until_Condition	Until_Log_File	Until_Log_Pos	Master_SSL_Allowed	Master_SSL_CA_File	Master_SSL_CA_Path	Master_SSL_Cert	Master_SSL_Cipher	Master_SSL_Key	Seconds_Behind_Master
 #	127.0.0.1	root	MASTER_MYPORT	1	master-bin.000001	18911	#	#	master-bin.000001	Yes	Yes							0		0	18911	#	None		0	No						#
-drop table t1,t2;
+drop table t1,t2,t3,t4;
diff --git a/mysql-test/t/func_str.test b/mysql-test/t/func_str.test
index 9dc6014ec56..efad2721ae5 100644
--- a/mysql-test/t/func_str.test
+++ b/mysql-test/t/func_str.test
@@ -608,3 +608,8 @@ insert t1 values ('ab'), ('abc'), ('abcd'), ('abcde');
 select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1;
 select * from (select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1) t;
 drop table t1;
+
+#
+# Bug #9854  hex() and out of range handling
+#
+select hex(29223372036854775809), hex(-29223372036854775809);
diff --git a/mysql-test/t/rpl_deadlock.test b/mysql-test/t/rpl_deadlock.test
index 3bcbb1d4567..eb4c5c33714 100644
--- a/mysql-test/t/rpl_deadlock.test
+++ b/mysql-test/t/rpl_deadlock.test
@@ -107,5 +107,5 @@ select * from t2;
 show slave status;
 
 connection master;
-drop table t1,t2;
+drop table t1,t2,t3,t4;
 sync_slave_with_master;
diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc
index dcb539476a1..2fd0f25e699 100644
--- a/sql/item_strfunc.cc
+++ b/sql/item_strfunc.cc
@@ -2380,9 +2380,22 @@ String *Item_func_hex::val_str(String *str)
   DBUG_ASSERT(fixed == 1);
   if (args[0]->result_type() != STRING_RESULT)
   {
-    /* Return hex of unsigned longlong value */
-    longlong dec= args[0]->val_int();
+    ulonglong dec;
     char ans[65],*ptr;
+    /* Return hex of unsigned longlong value */
+    if (args[0]->result_type() == REAL_RESULT ||
+        args[0]->result_type() == DECIMAL_RESULT)
+    {
+      double val= args[0]->val_real();
+      if ((val <= (double) LONGLONG_MIN) || 
+          (val >= (double) (ulonglong) ULONGLONG_MAX))
+        dec=  ~(longlong) 0;
+      else
+        dec= (ulonglong) (val + (val > 0 ? 0.5 : -0.5));
+    }
+    else
+      dec= (ulonglong) args[0]->val_int();
+
     if ((null_value= args[0]->null_value))
       return 0;
     ptr= longlong2str(dec,ans,16);