diff options
| author | Dmitry Shulga <dmitry.shulga@mariadb.com> | 2021-07-18 13:28:12 +0700 |
|---|---|---|
| committer | Dmitry Shulga <dmitry.shulga@mariadb.com> | 2021-07-18 13:28:12 +0700 |
| commit | ddbe57c727fc2fd25d26e52266e0ed2de4ebbb1d (patch) | |
| tree | 8ac386587d3c5b0d488f43634930024bf50753b5 /sql | |
| parent | 0f6e170c34700a2964556839c676c1b7768f3ffb (diff) | |
| download | mariadb-git-bb-10.2-MDEV-26145.tar.gz | |
MDEV-26145: Incorrect metadata is sent on running query with union in PS modebb-10.2-MDEV-26145
Test cases like the following one produce different result sets if it's run
with and without th option --ps-protocol.
CREATE TABLE t1(a INT);
--enable_metadata
(SELECT MAX(a) FROM t1) UNION (SELECT MAX(a) FROM t1);
--disable_metadata
DROP TABLE t1;
Result sets differ in metadata for the query
(SELECT MAX(a) FROM t1) UNION (SELECT MAX(a) FROM t1);
The reason for different content of query metadata is that for queries
with union the items being created on JOIN preparing phase is placed into
item_list from SELECT_LEX_UNIT whereas for queries without union item_list
from SELECT_LEX is used instead.
Diffstat (limited to 'sql')
| -rw-r--r-- | sql/sql_prepare.cc | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/sql/sql_prepare.cc b/sql/sql_prepare.cc index 922d7c92796..624bcb90cd5 100644 --- a/sql/sql_prepare.cc +++ b/sql/sql_prepare.cc @@ -1674,7 +1674,12 @@ static int mysql_test_select(Prepared_statement *stmt, if (!lex->describe && !thd->lex->analyze_stmt && !stmt->is_sql_prepare()) { /* Make copy of item list, as change_columns may change it */ - List<Item> fields(lex->select_lex.item_list); + SELECT_LEX_UNIT* master_unit= unit->first_select()->master_unit(); + bool is_union_op= + master_unit->is_union() || master_unit->fake_select_lex; + + List<Item> fields(is_union_op ? unit->item_list : + lex->select_lex.item_list); /* Change columns if a procedure like analyse() */ if (unit->last_procedure && unit->last_procedure->change_columns(thd, fields)) |