Hi! Sergei Golubchik <serg@mariadb.org> schrieb am Sa., 16. Okt. 2021, 10:23:
Hi, Oleksandr!
On Oct 16, Oleksandr Byelkin wrote:
revision-id: fcf2c5fff14 (mariadb-10.2.40-78-gfcf2c5fff14) parent(s): d5a15f04f4a author: Oleksandr Byelkin committer: Oleksandr Byelkin timestamp: 2021-10-01 14:46:22 +0200 message:
MDEV-26299: Some views force server (and mysqldump) to generate invalid SQL for their definitions
Do not print illegal table field names for non-top-level SELECT list, they will not be refered in any case but create problem for parsing of printed result.
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index ff584e936b7..ebee9c85791 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -25797,6 +25797,11 @@ void st_select_lex::print(THD *thd, String *str, enum_query_type query_type)
//Item List bool first= 1; + /* + outer_select() can not be used here because it is for name resolution + and will return NULL at any end of name resolution chain (view/derived) + */ + bool top_level= (get_master()->get_master() == 0); List_iterator_fast<Item> it(item_list); Item *item; while ((item= it++)) @@ -25806,7 +25811,8 @@ void st_select_lex::print(THD *thd, String *str, enum_query_type query_type) else str->append(',');
- if (is_subquery_function() && item->is_autogenerated_name) + if ((is_subquery_function() && item->is_autogenerated_name) || + !item->name)
Where can item->name be NULL? I thought the either specified by the user or autogenerated, but never NULL.
Or internally created with null name.
{ /* Do not print auto-generated aliases in subqueries. It has no
purpose
@@ -25815,7 +25821,26 @@ void st_select_lex::print(THD *thd, String *str, enum_query_type query_type) item->print(str, query_type); } else - item->print_item_w_name(str, query_type); + { + /* + Despite presence of item->name_length it is incorrect in many cases + till we start using LEX_STRING for the name. + */ + size_t len= strlen(item->name); + + /* + Do not print illegal names (if it is not top level SELECT). + Top level view checked (and correct name are assigned), + other cases of top level SELECT are not important, because + it is not "table field". + */ + if (top_level || + !item->is_autogenerated_name || + !check_table_name(item->name, len, TRUE))
why check_table_name() if it isn't a table? it's an incorrect check to use for columns.
A derived table AKA a subquery in the FROM clause is still a table. For other things I have no idea why we check AS part for correspondence to table name rules, but we do it on parsing.
+ item->print_item_w_name(str, query_type); + else + item->print(str, query_type); + } }
/*
Regards, Sergei VP of MariaDB Server Engineering and security@mariadb.org