Added a test case for Bug#8009.

sql/item.cc:
  Fixed Bug#8009.

mysql-test/r/select.result

@@ -2509,3 +2509,9 @@ AND FK_firma_id = 2;
 COUNT(*)
 0
 drop table t1;
+CREATE TABLE t1 (b BIGINT(20) UNSIGNED NOT NULL, PRIMARY KEY (b));
+INSERT INTO t1 VALUES (0x8000000000000000);
+SELECT b FROM t1 WHERE b=0x8000000000000000;
+b
+9223372036854775808
+DROP TABLE t1;

mysql-test/t/select.test

@@ -2051,3 +2051,12 @@ SELECT COUNT(*) FROM t1 WHERE
 AND FK_firma_id = 2;
 
 drop table t1;
+
+#
+# Test for Bug#8009, SELECT failed on bigint unsigned when using HEX
+#
+
+CREATE TABLE t1 (b BIGINT(20) UNSIGNED NOT NULL, PRIMARY KEY (b));
+INSERT INTO t1 VALUES (0x8000000000000000);
+SELECT b FROM t1 WHERE b=0x8000000000000000;
+DROP TABLE t1;

sql/item.cc

@@ -2107,6 +2107,7 @@ Item_varbinary::Item_varbinary(const char *str, uint str_length)
   *ptr=0;					// Keep purify happy
   collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
   fixed= 1;
+  unsigned_flag= 1;
 }
 
 longlong Item_varbinary::val_int()