diff --git a/mysql-test/main/func_str.result b/mysql-test/main/func_str.result
index b5217d98fd2..52bfd3f0e3e 100644
--- a/mysql-test/main/func_str.result
+++ b/mysql-test/main/func_str.result
@@ -748,7 +748,7 @@ t1	CREATE TABLE `t1` (
   `bin(130)` varchar(64) DEFAULT NULL,
   `oct(130)` varchar(64) DEFAULT NULL,
   `conv(130,16,10)` varchar(64) DEFAULT NULL,
-  `hex(130)` varchar(6) DEFAULT NULL,
+  `hex(130)` varchar(16) DEFAULT NULL,
   `char(130)` varbinary(4) DEFAULT NULL,
   `format(130,10)` varchar(25) DEFAULT NULL,
   `left(_latin2'a',1)` varchar(1) CHARACTER SET latin2 COLLATE latin2_general_ci DEFAULT NULL,
diff --git a/mysql-test/main/type_float.result b/mysql-test/main/type_float.result
index fa850cf9b34..e944b4bb64f 100644
--- a/mysql-test/main/type_float.result
+++ b/mysql-test/main/type_float.result
@@ -1206,3 +1206,82 @@ DROP VIEW v1;
 #
 # End of 10.4 tests
 #
+#
+# Start of 10.5 tests
+#
+#
+# MDEV-20548 Unexpected error on CREATE..SELECT HEX(num)
+#
+SET sql_mode=STRICT_ALL_TABLES;
+CREATE TABLE t1 AS SELECT HEX(-2e0) AS h;
+SELECT * FROM t1;
+h
+FFFFFFFFFFFFFFFE
+SHOW COLUMNS IN t1;
+Field	Type	Null	Key	Default	Extra
+h	varchar(16)	YES		NULL	
+DROP TABLE t1;
+CREATE TABLE t1 AS SELECT HEX(-1e0) AS h;
+SELECT * FROM t1;
+h
+FFFFFFFFFFFFFFFF
+SHOW COLUMNS IN t1;
+Field	Type	Null	Key	Default	Extra
+h	varchar(16)	YES		NULL	
+DROP TABLE t1;
+CREATE TABLE t1 AS SELECT HEX(1e0) AS h;
+SELECT * FROM t1;
+h
+1
+SHOW COLUMNS IN t1;
+Field	Type	Null	Key	Default	Extra
+h	varchar(16)	YES		NULL	
+DROP TABLE t1;
+CREATE TABLE t1 AS SELECT HEX(2e0) AS h;
+SELECT * FROM t1;
+h
+2
+SHOW COLUMNS IN t1;
+Field	Type	Null	Key	Default	Extra
+h	varchar(16)	YES		NULL	
+DROP TABLE t1;
+CREATE TABLE t1 (a FLOAT);
+INSERT INTO t1 VALUES (-1e38),(-255),(-2),(-1),(+1),(+2),(255),(1e38);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2 ORDER BY a;
+a	h
+-1e38	FFFFFFFFFFFFFFFF
+-255	FFFFFFFFFFFFFF01
+-2	FFFFFFFFFFFFFFFE
+-1	FFFFFFFFFFFFFFFF
+1	1
+2	2
+255	FF
+1e38	FFFFFFFFFFFFFFFF
+SHOW COLUMNS IN t2;
+Field	Type	Null	Key	Default	Extra
+a	float	YES		NULL	
+h	varchar(16)	YES		NULL	
+DROP TABLE t1, t2;
+CREATE TABLE t1 (a DOUBLE);
+INSERT INTO t1 VALUES (-1e308),(-255),(-2),(-1),(+1),(+2),(255),(1e308);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2 ORDER BY a;
+a	h
+-1e308	FFFFFFFFFFFFFFFF
+-255	FFFFFFFFFFFFFF01
+-2	FFFFFFFFFFFFFFFE
+-1	FFFFFFFFFFFFFFFF
+1	1
+2	2
+255	FF
+1e308	FFFFFFFFFFFFFFFF
+SHOW COLUMNS IN t2;
+Field	Type	Null	Key	Default	Extra
+a	double	YES		NULL	
+h	varchar(16)	YES		NULL	
+DROP TABLE t1, t2;
+SET sql_mode=DEFAULT;
+#
+# End of 10.5 tests
+#
diff --git a/mysql-test/main/type_float.test b/mysql-test/main/type_float.test
index 12ae5937533..1cc5cc94267 100644
--- a/mysql-test/main/type_float.test
+++ b/mysql-test/main/type_float.test
@@ -745,3 +745,54 @@ DROP VIEW v1;
 --echo #
 --echo # End of 10.4 tests
 --echo #
+
+--echo #
+--echo # Start of 10.5 tests
+--echo #
+
+--echo #
+--echo # MDEV-20548 Unexpected error on CREATE..SELECT HEX(num)
+--echo #
+
+SET sql_mode=STRICT_ALL_TABLES;
+
+CREATE TABLE t1 AS SELECT HEX(-2e0) AS h;
+SELECT * FROM t1;
+SHOW COLUMNS IN t1;
+DROP TABLE t1;
+
+CREATE TABLE t1 AS SELECT HEX(-1e0) AS h;
+SELECT * FROM t1;
+SHOW COLUMNS IN t1;
+DROP TABLE t1;
+
+CREATE TABLE t1 AS SELECT HEX(1e0) AS h;
+SELECT * FROM t1;
+SHOW COLUMNS IN t1;
+DROP TABLE t1;
+
+CREATE TABLE t1 AS SELECT HEX(2e0) AS h;
+SELECT * FROM t1;
+SHOW COLUMNS IN t1;
+DROP TABLE t1;
+
+
+CREATE TABLE t1 (a FLOAT);
+INSERT INTO t1 VALUES (-1e38),(-255),(-2),(-1),(+1),(+2),(255),(1e38);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2 ORDER BY a;
+SHOW COLUMNS IN t2;
+DROP TABLE t1, t2;
+
+CREATE TABLE t1 (a DOUBLE);
+INSERT INTO t1 VALUES (-1e308),(-255),(-2),(-1),(+1),(+2),(255),(1e308);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2 ORDER BY a;
+SHOW COLUMNS IN t2;
+DROP TABLE t1, t2;
+
+SET sql_mode=DEFAULT;
+
+--echo #
+--echo # End of 10.5 tests
+--echo #
diff --git a/mysql-test/main/type_int.result b/mysql-test/main/type_int.result
index c25b213c7c4..0b933a0de15 100644
--- a/mysql-test/main/type_int.result
+++ b/mysql-test/main/type_int.result
@@ -1686,5 +1686,166 @@ c0
 127
 drop table t1;
 #
+# MDEV-20548 Unexpected error on CREATE..SELECT HEX(num)
+#
+SET sql_mode=STRICT_ALL_TABLES;
+CREATE TABLE t1 AS SELECT HEX(-2) AS h;
+SELECT * FROM t1;
+h
+FFFFFFFFFFFFFFFE
+SHOW COLUMNS IN t1;
+Field	Type	Null	Key	Default	Extra
+h	varchar(16)	YES		NULL	
+DROP TABLE t1;
+CREATE TABLE t1 AS SELECT HEX(-1) AS h;
+SELECT * FROM t1;
+h
+FFFFFFFFFFFFFFFF
+SHOW COLUMNS IN t1;
+Field	Type	Null	Key	Default	Extra
+h	varchar(16)	YES		NULL	
+DROP TABLE t1;
+CREATE TABLE t1 AS SELECT HEX(1) AS h;
+SELECT * FROM t1;
+h
+1
+SHOW COLUMNS IN t1;
+Field	Type	Null	Key	Default	Extra
+h	varchar(16)	YES		NULL	
+DROP TABLE t1;
+CREATE TABLE t1 AS SELECT HEX(2) AS h;
+SELECT * FROM t1;
+h
+2
+SHOW COLUMNS IN t1;
+Field	Type	Null	Key	Default	Extra
+h	varchar(16)	YES		NULL	
+DROP TABLE t1;
+CREATE TABLE t1 (a TINYINT);
+INSERT INTO t1 VALUES (-0x80),(-2),(-1),(1),(2),(0x7f);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2;
+a	h
+-128	FFFFFFFFFFFFFF80
+-2	FFFFFFFFFFFFFFFE
+-1	FFFFFFFFFFFFFFFF
+1	1
+2	2
+127	7F
+SHOW COLUMNS IN t2;
+Field	Type	Null	Key	Default	Extra
+a	tinyint(4)	YES		NULL	
+h	varchar(16)	YES		NULL	
+DROP TABLE t1, t2;
+CREATE TABLE t1 (a SMALLINT);
+INSERT INTO t1 VALUES (-0x8000),(-0x80),(-2),(-1),(1),(2),(0x7f),(0x7fff);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2;
+a	h
+-32768	FFFFFFFFFFFF8000
+-128	FFFFFFFFFFFFFF80
+-2	FFFFFFFFFFFFFFFE
+-1	FFFFFFFFFFFFFFFF
+1	1
+2	2
+127	7F
+32767	7FFF
+SHOW COLUMNS IN t2;
+Field	Type	Null	Key	Default	Extra
+a	smallint(6)	YES		NULL	
+h	varchar(16)	YES		NULL	
+DROP TABLE t1, t2;
+CREATE TABLE t1 (a MEDIUMINT);
+INSERT INTO t1 VALUES (-0x800000);
+INSERT INTO t1 VALUES (-0x8000),(-0x80),(-2),(-1),(1),(2),(0x7f),(0x7fff);
+INSERT INTO t1 VALUES (0x7fffff);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2;
+a	h
+-8388608	FFFFFFFFFF800000
+-32768	FFFFFFFFFFFF8000
+-128	FFFFFFFFFFFFFF80
+-2	FFFFFFFFFFFFFFFE
+-1	FFFFFFFFFFFFFFFF
+1	1
+2	2
+127	7F
+32767	7FFF
+8388607	7FFFFF
+SHOW COLUMNS IN t2;
+Field	Type	Null	Key	Default	Extra
+a	mediumint(9)	YES		NULL	
+h	varchar(16)	YES		NULL	
+DROP TABLE t1, t2;
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (-0x80000000);
+INSERT INTO t1 VALUES (-0x800000);
+INSERT INTO t1 VALUES (-0x8000),(-0x80),(-2),(-1),(1),(2),(0x7f),(0x7fff);
+INSERT INTO t1 VALUES (0x7fffff);
+INSERT INTO t1 VALUES (0x7fffffff);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2;
+a	h
+-2147483648	FFFFFFFF80000000
+-8388608	FFFFFFFFFF800000
+-32768	FFFFFFFFFFFF8000
+-128	FFFFFFFFFFFFFF80
+-2	FFFFFFFFFFFFFFFE
+-1	FFFFFFFFFFFFFFFF
+1	1
+2	2
+127	7F
+32767	7FFF
+8388607	7FFFFF
+2147483647	7FFFFFFF
+SHOW COLUMNS IN t2;
+Field	Type	Null	Key	Default	Extra
+a	int(11)	YES		NULL	
+h	varchar(16)	YES		NULL	
+DROP TABLE t1, t2;
+CREATE TABLE t1 (a BIGINT);
+INSERT INTO t1 VALUES (-0x8000000000000000);
+INSERT INTO t1 VALUES (-0x80000000000000);
+INSERT INTO t1 VALUES (-0x800000000000);
+INSERT INTO t1 VALUES (-0x8000000000);
+INSERT INTO t1 VALUES (-0x80000000);
+INSERT INTO t1 VALUES (-0x800000);
+INSERT INTO t1 VALUES (-0x8000),(-0x80),(-2),(-1),(1),(2),(0x7f),(0x7fff);
+INSERT INTO t1 VALUES (0x7fffff);
+INSERT INTO t1 VALUES (0x7fffffff);
+INSERT INTO t1 VALUES (0x7fffffffff);
+INSERT INTO t1 VALUES (0x7fffffffffff);
+INSERT INTO t1 VALUES (0x7fffffffffffff);
+INSERT INTO t1 VALUES (0x7fffffffffffffff);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2;
+a	h
+-9223372036854775808	8000000000000000
+-36028797018963968	FF80000000000000
+-140737488355328	FFFF800000000000
+-549755813888	FFFFFF8000000000
+-2147483648	FFFFFFFF80000000
+-8388608	FFFFFFFFFF800000
+-32768	FFFFFFFFFFFF8000
+-128	FFFFFFFFFFFFFF80
+-2	FFFFFFFFFFFFFFFE
+-1	FFFFFFFFFFFFFFFF
+1	1
+2	2
+127	7F
+32767	7FFF
+8388607	7FFFFF
+2147483647	7FFFFFFF
+549755813887	7FFFFFFFFF
+140737488355327	7FFFFFFFFFFF
+36028797018963967	7FFFFFFFFFFFFF
+9223372036854775807	7FFFFFFFFFFFFFFF
+SHOW COLUMNS IN t2;
+Field	Type	Null	Key	Default	Extra
+a	bigint(20)	YES		NULL	
+h	varchar(16)	YES		NULL	
+DROP TABLE t1, t2;
+SET sql_mode=DEFAULT;
+#
 # End of 10.5 tests
 #
diff --git a/mysql-test/main/type_int.test b/mysql-test/main/type_int.test
index c339bfa1834..290edb80410 100644
--- a/mysql-test/main/type_int.test
+++ b/mysql-test/main/type_int.test
@@ -564,6 +564,88 @@ insert into t1 values (-128);
 select * from t1 where 18446744073700599371 > c0;
 drop table t1;
 
+--echo #
+--echo # MDEV-20548 Unexpected error on CREATE..SELECT HEX(num)
+--echo #
+
+SET sql_mode=STRICT_ALL_TABLES;
+
+CREATE TABLE t1 AS SELECT HEX(-2) AS h;
+SELECT * FROM t1;
+SHOW COLUMNS IN t1;
+DROP TABLE t1;
+
+CREATE TABLE t1 AS SELECT HEX(-1) AS h;
+SELECT * FROM t1;
+SHOW COLUMNS IN t1;
+DROP TABLE t1;
+
+CREATE TABLE t1 AS SELECT HEX(1) AS h;
+SELECT * FROM t1;
+SHOW COLUMNS IN t1;
+DROP TABLE t1;
+
+CREATE TABLE t1 AS SELECT HEX(2) AS h;
+SELECT * FROM t1;
+SHOW COLUMNS IN t1;
+DROP TABLE t1;
+
+CREATE TABLE t1 (a TINYINT);
+INSERT INTO t1 VALUES (-0x80),(-2),(-1),(1),(2),(0x7f);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2;
+SHOW COLUMNS IN t2;
+DROP TABLE t1, t2;
+
+CREATE TABLE t1 (a SMALLINT);
+INSERT INTO t1 VALUES (-0x8000),(-0x80),(-2),(-1),(1),(2),(0x7f),(0x7fff);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2;
+SHOW COLUMNS IN t2;
+DROP TABLE t1, t2;
+
+CREATE TABLE t1 (a MEDIUMINT);
+INSERT INTO t1 VALUES (-0x800000);
+INSERT INTO t1 VALUES (-0x8000),(-0x80),(-2),(-1),(1),(2),(0x7f),(0x7fff);
+INSERT INTO t1 VALUES (0x7fffff);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2;
+SHOW COLUMNS IN t2;
+DROP TABLE t1, t2;
+
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (-0x80000000);
+INSERT INTO t1 VALUES (-0x800000);
+INSERT INTO t1 VALUES (-0x8000),(-0x80),(-2),(-1),(1),(2),(0x7f),(0x7fff);
+INSERT INTO t1 VALUES (0x7fffff);
+INSERT INTO t1 VALUES (0x7fffffff);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2;
+SHOW COLUMNS IN t2;
+DROP TABLE t1, t2;
+
+CREATE TABLE t1 (a BIGINT);
+INSERT INTO t1 VALUES (-0x8000000000000000);
+INSERT INTO t1 VALUES (-0x80000000000000);
+INSERT INTO t1 VALUES (-0x800000000000);
+INSERT INTO t1 VALUES (-0x8000000000);
+INSERT INTO t1 VALUES (-0x80000000);
+INSERT INTO t1 VALUES (-0x800000);
+INSERT INTO t1 VALUES (-0x8000),(-0x80),(-2),(-1),(1),(2),(0x7f),(0x7fff);
+INSERT INTO t1 VALUES (0x7fffff);
+INSERT INTO t1 VALUES (0x7fffffff);
+INSERT INTO t1 VALUES (0x7fffffffff);
+INSERT INTO t1 VALUES (0x7fffffffffff);
+INSERT INTO t1 VALUES (0x7fffffffffffff);
+INSERT INTO t1 VALUES (0x7fffffffffffffff);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2;
+SHOW COLUMNS IN t2;
+DROP TABLE t1, t2;
+
+SET sql_mode=DEFAULT;
+
+
 --echo #
 --echo # End of 10.5 tests
 --echo #
diff --git a/mysql-test/main/type_newdecimal.result b/mysql-test/main/type_newdecimal.result
index 5f959d83438..9bd848ddea9 100644
--- a/mysql-test/main/type_newdecimal.result
+++ b/mysql-test/main/type_newdecimal.result
@@ -2801,3 +2801,77 @@ DROP TABLE t2,t1;
 #
 # End of 10.4 tests
 #
+#
+# Start of 10.5 tests
+#
+#
+# MDEV-20548 Unexpected error on CREATE..SELECT HEX(num)
+#
+SET sql_mode=STRICT_ALL_TABLES;
+CREATE TABLE t1 AS SELECT HEX(-2) AS h;
+SELECT * FROM t1;
+h
+FFFFFFFFFFFFFFFE
+SHOW COLUMNS IN t1;
+Field	Type	Null	Key	Default	Extra
+h	varchar(16)	YES		NULL	
+DROP TABLE t1;
+CREATE TABLE t1 AS SELECT HEX(-1) AS h;
+SELECT * FROM t1;
+h
+FFFFFFFFFFFFFFFF
+SHOW COLUMNS IN t1;
+Field	Type	Null	Key	Default	Extra
+h	varchar(16)	YES		NULL	
+DROP TABLE t1;
+CREATE TABLE t1 AS SELECT HEX(+1) AS h;
+SELECT * FROM t1;
+h
+1
+SHOW COLUMNS IN t1;
+Field	Type	Null	Key	Default	Extra
+h	varchar(16)	YES		NULL	
+DROP TABLE t1;
+CREATE TABLE t1 AS SELECT HEX(+2) AS h;
+SELECT * FROM t1;
+h
+2
+SHOW COLUMNS IN t1;
+Field	Type	Null	Key	Default	Extra
+h	varchar(16)	YES		NULL	
+DROP TABLE t1;
+CREATE TABLE t1 (a DECIMAL(41,1));
+INSERT INTO t1 VALUES (-1000000000000000000000000000000000000000);
+INSERT INTO t1 VALUES (-0x8000000000);
+INSERT INTO t1 VALUES (-0x80000000),(-0x800000),(-0x8000),(-0x80),(-2),(-1);
+INSERT INTO t1 VALUES (1),(2),(128),(0x7fff),(0x7fffff),(0x7fffffff);
+INSERT INTO t1 VALUES (+0x7fffffffff);
+INSERT INTO t1 VALUES (+1000000000000000000000000000000000000000);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2 ORDER BY a;
+a	h
+-1000000000000000000000000000000000000000.0	FFFFFFFFFFFFFFFF
+-549755813888.0	FFFFFF8000000000
+-2147483648.0	FFFFFFFF80000000
+-8388608.0	FFFFFFFFFF800000
+-32768.0	FFFFFFFFFFFF8000
+-128.0	FFFFFFFFFFFFFF80
+-2.0	FFFFFFFFFFFFFFFE
+-1.0	FFFFFFFFFFFFFFFF
+1.0	1
+2.0	2
+128.0	80
+32767.0	7FFF
+8388607.0	7FFFFF
+2147483647.0	7FFFFFFF
+549755813887.0	7FFFFFFFFF
+1000000000000000000000000000000000000000.0	FFFFFFFFFFFFFFFF
+SHOW COLUMNS IN t2;
+Field	Type	Null	Key	Default	Extra
+a	decimal(41,1)	YES		NULL	
+h	varchar(16)	YES		NULL	
+DROP TABLE t1, t2;
+SET sql_mode=DEFAULT;
+#
+# End of 10.5 tests
+#
diff --git a/mysql-test/main/type_newdecimal.test b/mysql-test/main/type_newdecimal.test
index 77ef338f93e..33e56da7da8 100644
--- a/mysql-test/main/type_newdecimal.test
+++ b/mysql-test/main/type_newdecimal.test
@@ -2000,3 +2000,51 @@ DROP TABLE t2,t1;
 --echo #
 --echo # End of 10.4 tests
 --echo #
+
+--echo #
+--echo # Start of 10.5 tests
+--echo #
+
+--echo #
+--echo # MDEV-20548 Unexpected error on CREATE..SELECT HEX(num)
+--echo #
+
+SET sql_mode=STRICT_ALL_TABLES;
+
+CREATE TABLE t1 AS SELECT HEX(-2) AS h;
+SELECT * FROM t1;
+SHOW COLUMNS IN t1;
+DROP TABLE t1;
+
+CREATE TABLE t1 AS SELECT HEX(-1) AS h;
+SELECT * FROM t1;
+SHOW COLUMNS IN t1;
+DROP TABLE t1;
+
+CREATE TABLE t1 AS SELECT HEX(+1) AS h;
+SELECT * FROM t1;
+SHOW COLUMNS IN t1;
+DROP TABLE t1;
+
+CREATE TABLE t1 AS SELECT HEX(+2) AS h;
+SELECT * FROM t1;
+SHOW COLUMNS IN t1;
+DROP TABLE t1;
+
+CREATE TABLE t1 (a DECIMAL(41,1));
+INSERT INTO t1 VALUES (-1000000000000000000000000000000000000000);
+INSERT INTO t1 VALUES (-0x8000000000);
+INSERT INTO t1 VALUES (-0x80000000),(-0x800000),(-0x8000),(-0x80),(-2),(-1);
+INSERT INTO t1 VALUES (1),(2),(128),(0x7fff),(0x7fffff),(0x7fffffff);
+INSERT INTO t1 VALUES (+0x7fffffffff);
+INSERT INTO t1 VALUES (+1000000000000000000000000000000000000000);
+CREATE TABLE t2 AS SELECT a, HEX(a) AS h FROM t1;
+SELECT * FROM t2 ORDER BY a;
+SHOW COLUMNS IN t2;
+DROP TABLE t1, t2;
+
+SET sql_mode=DEFAULT;
+
+--echo #
+--echo # End of 10.5 tests
+--echo #
diff --git a/plugin/type_test/mysql-test/type_test/type_test_double.result b/plugin/type_test/mysql-test/type_test/type_test_double.result
index edcfdc0eff8..ff009885072 100644
--- a/plugin/type_test/mysql-test/type_test/type_test_double.result
+++ b/plugin/type_test/mysql-test/type_test/type_test_double.result
@@ -83,7 +83,7 @@ SELECT HEX(a), a;
 END;
 $$
 Catalog	Database	Table	Table_alias	Column	Column_alias	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
-def					HEX(a)	253	44	3	Y	0	0	8
+def					HEX(a)	253	16	3	Y	0	0	8
 def				a	a	5	22	3	Y	32768	31	63
 HEX(a)	a
 100	256
diff --git a/plugin/type_test/mysql-test/type_test/type_test_int8.result b/plugin/type_test/mysql-test/type_test/type_test_int8.result
index 75fcf1f2f5e..4d7175ffe69 100644
--- a/plugin/type_test/mysql-test/type_test/type_test_int8.result
+++ b/plugin/type_test/mysql-test/type_test/type_test_int8.result
@@ -62,7 +62,7 @@ SELECT HEX(a), a;
 END;
 $$
 Catalog	Database	Table	Table_alias	Column	Column_alias	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
-def					HEX(a)	253	40	3	Y	0	0	8
+def					HEX(a)	253	16	3	Y	0	0	8
 def				a	a	8	20	3	Y	32768	0	63
 HEX(a)	a
 100	256
diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc
index c36a2a5c072..8c8bb04edef 100644
--- a/sql/item_strfunc.cc
+++ b/sql/item_strfunc.cc
@@ -3770,9 +3770,11 @@ String *Item_func_hex::val_str_ascii_from_val_real(String *str)
     return 0;
   if ((val <= (double) LONGLONG_MIN) ||
       (val >= (double) (ulonglong) ULONGLONG_MAX))
-    dec= ~(longlong) 0;
+    dec= ULONGLONG_MAX;
+  else if (val < 0)
+    dec= (ulonglong) (longlong) (val - 0.5);
   else
-    dec= (ulonglong) (val + (val > 0 ? 0.5 : -0.5));
+    dec= (ulonglong) (val + 0.5);
   return str->set_hex(dec) ? make_empty_result(str) : str;
 }
 
diff --git a/sql/item_strfunc.h b/sql/item_strfunc.h
index e40726ce255..42a41242e01 100644
--- a/sql/item_strfunc.h
+++ b/sql/item_strfunc.h
@@ -1379,10 +1379,20 @@ public:
   }
   bool fix_length_and_dec() override
   {
+    m_arg0_type_handler= args[0]->type_handler();
     collation.set(default_charset(), DERIVATION_COERCIBLE, MY_REPERTOIRE_ASCII);
     decimals=0;
-    fix_char_length(args[0]->max_length * 2);
-    m_arg0_type_handler= args[0]->type_handler();
+    /*
+      Reserve space for 16 characters for signed numeric data types:
+        hex(-1) -> 'FFFFFFFFFFFFFFFF'.
+      For unsigned numeric types, HEX() can create too large columns.
+      This should be eventually fixed to create minimum possible columns.
+    */
+    const Type_handler_numeric *tn=
+      dynamic_cast<const Type_handler_numeric*>(m_arg0_type_handler);
+    size_t char_length= (tn && !(tn->flags() & UNSIGNED_FLAG)) ?
+                        (size_t) 16 : (size_t) args[0]->max_length * 2;
+    fix_char_length(char_length);
     return FALSE;
   }
   Item *get_copy(THD *thd) override