This is another attempt to fix mdev-16473.

The previous correction of the patch for mdev-16473 did not work
correctly for the databases whose names started with '*'.
Added a test case with a database named "*".

mysql-test/r/cte_nonrecursive.result

@@ -1511,4 +1511,15 @@ a	a
 3	3
 1	1
 drop database db_mdev_16473;
+create database `*` ;
+create table `*`.t1 (a int);
+insert into `*`.t1 values (2), (7), (3), (1);
+use `*`;
+select * from t1;
+a
+2
+7
+3
+1
+drop database `*`;
 use test;

mysql-test/t/cte_nonrecursive.test

@@ -1056,4 +1056,11 @@ select * from cte, db_mdev_16473.t1 as t where cte.a=t.a;
 
 drop database db_mdev_16473;
 
+create database `*` ;
+create table `*`.t1 (a int);
+insert into `*`.t1 values (2), (7), (3), (1);
+use `*`;
+select * from t1;
+drop database `*`;
+
 use test;

sql/sql_base.cc

@@ -3331,7 +3331,7 @@ open_and_process_table(THD *thd, LEX *lex, TABLE_LIST *tables,
     Not a placeholder: must be a base/temporary table or a view. Let us open it.
   */
 
-  if (tables->db[0] == no_db[0])
+  if (tables->no_default_db && !tables->is_fqtn)
   {
     my_message(ER_NO_DB_ERROR, ER(ER_NO_DB_ERROR), MYF(0));
     error= TRUE;

sql/sql_class.h

@@ -3959,7 +3959,10 @@ public:
         my_message(ER_NO_DB_ERROR, ER(ER_NO_DB_ERROR), MYF(0));
         return TRUE;
       }
-      /* This will allow to throw an error later for non-CTE references */
+      /*
+        It does not matter what database name is set in this case
+        because it will never be used after parser stage
+      */
       *p_db_length= strlen(no_db);
       *p_db= strmake(no_db, *p_db_length);
     }

sql/sql_parse.cc

@@ -139,7 +139,7 @@ static bool execute_show_status(THD *, TABLE_LIST *);
 static bool check_rename_table(THD *, TABLE_LIST *, TABLE_LIST *);
 
 const char *any_db="*any*";	// Special symbol for check_access
-const char *no_db="*none*";     // Used when no default db is set
+const char *no_db="*";          // Used when no default db is set
 
 const LEX_STRING command_name[257]={
   { C_STRING_WITH_LEN("Sleep") },           //0
@@ -8188,6 +8188,7 @@ TABLE_LIST *st_select_lex::add_table_to_list(THD *thd,
     DBUG_RETURN(0);
   else
     ptr->is_fqtn= FALSE;
+  ptr->no_default_db= !thd->db && !(lex->sphead && lex->sphead->m_name.str);
 
   ptr->alias= alias_str;
   ptr->is_alias= alias ? TRUE : FALSE;

sql/table.h

@@ -2095,7 +2095,8 @@ struct TABLE_LIST
       qualified name (<db_name>.<table_name>).
   */
   bool          is_fqtn;
-
+  /** TRUE if no default database is defined for the table name */
+  bool          no_default_db;
   /* TRUE <=> derived table should be filled right after optimization. */
   bool          fill_me;
   /* TRUE <=> view/DT is merged. */