Details
Description
(I've found this issue when fixing MDEV-25202. the fix is a part of MDEV-25202 fix )
ON expressions inside a join nest cannot refer to tables outside the nest. This can be "circumvented" by putting the outside reference into a subquery.
create table t1 (a int, b int); |
create table t2 (c int, d int); |
create table t3 (e int, f int); |
create table t4 (g int, h int); |
A reference to t1.a in the ON expression produces an error, as expected:
explain
|
select * |
from |
t1 left join |
(t2
|
join |
t3 on |
(t3.f=t1.a)
|
) on (t2.c=t1.a ); |
ERROR 1054 (42S22): Unknown column 't1.a' in 'on clause'
|
A reference from a subquery does not produce an error:
explain
|
select * |
from |
t1 left join |
(t2
|
join |
t3 on |
(t3.f=(select max(g) from t4 where t4.h=t1.a)) |
) on (t2.c=t1.a ); |
This is wrong/
Attachments
Issue Links
- relates to
-
MDEV-25346 Server crashes in Item_field::fix_outer_field upon subquery with unknown column
- Closed
Activity
Sergey,
The above fix should be applied to 10.4 (without test cases). The test cases must be added to the corresponding fix that would be good for 10.2, 10.3.
The above suggested fix for this issue causes MDEV-25346. Apply the patch for MDEV-25346 together with the above fix.
Here's the diff for those who will merge the patch into 10.4:
diff --git a/mysql-test/main/join_outer.result b/mysql-test/main/join_outer.result
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index c92b8e6..362335a 100644
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--- a/mysql-test/main/join_outer.result
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+++ b/mysql-test/main/join_outer.result
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@@ -2687,6 +2687,46 @@ id timestamp modifiedBy id REV REVTYPE profile_id id REV person_id id REV
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DROP TABLE t1,t2,t3,t4;
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# end of 10.1 tests
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#
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+# MDEV-25362: name resolution for subqueries in ON expressions
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+#
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+create table t1 (a int, b int);
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+create table t2 (c int, d int);
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+create table t3 (e int, f int);
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+create table t4 (g int, h int);
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+explain
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+select *
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+from
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+t1 left join
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+(t2
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+join
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+t3 on
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+(t3.f=t1.a)
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+) on (t2.c=t1.a );
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+ERROR 42S22: Unknown column 't1.a' in 'on clause'
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+explain
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+select *
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+from
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+t1 left join
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+(t2
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+join
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+t3 on
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+(t3.f=(select max(g) from t4 where t4.h=t1.a))
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+) on (t2.c=t1.a );
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+ERROR 42S22: Unknown column 't1.a' in 'where clause'
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+drop table t1,t2,t3,t4;
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+create table t1 (a int);
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+insert into t1 values (1),(2);
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+create table t2 (b int);
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+insert into t2 values (1),(2);
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+create table t3 (c int);
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+insert into t3 values (1),(2);
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+select * from ( select * from t1 left join t2
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+on b in (select x from t3 as sq1)
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+) as sq2;
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+ERROR 42S22: Unknown column 'x' in 'field list'
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+drop table t1,t2,t3;
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+# end of 10.2 tests
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+#
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# MDEV-17518: Range optimization doesn't use ON expressions from nested outer joins
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#
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create table t1(a int);
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diff --git a/mysql-test/main/join_outer.test b/mysql-test/main/join_outer.test
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index f835d8a..bf75a52 100644
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--- a/mysql-test/main/join_outer.test
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+++ b/mysql-test/main/join_outer.test
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@@ -2192,6 +2192,56 @@ DROP TABLE t1,t2,t3,t4;
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--echo # end of 10.1 tests
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--echo #
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+--echo # MDEV-25362: name resolution for subqueries in ON expressions
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+--echo #
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+
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+create table t1 (a int, b int);
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+create table t2 (c int, d int);
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+create table t3 (e int, f int);
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+create table t4 (g int, h int);
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+
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+--error ER_BAD_FIELD_ERROR
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+explain
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+select *
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+from
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+ t1 left join
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+ (t2
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+ join
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+ t3 on
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+ (t3.f=t1.a)
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+ ) on (t2.c=t1.a );
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+
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+# This must produce an error:
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+--error ER_BAD_FIELD_ERROR
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+explain
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+select *
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+from
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+ t1 left join
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+ (t2
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+ join
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+ t3 on
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+ (t3.f=(select max(g) from t4 where t4.h=t1.a))
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+ ) on (t2.c=t1.a );
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+
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+drop table t1,t2,t3,t4;
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+
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+create table t1 (a int);
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+insert into t1 values (1),(2);
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+create table t2 (b int);
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+insert into t2 values (1),(2);
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+create table t3 (c int);
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+insert into t3 values (1),(2);
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+
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+--error ER_BAD_FIELD_ERROR
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+select * from ( select * from t1 left join t2
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+ on b in (select x from t3 as sq1)
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+ ) as sq2;
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+
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+drop table t1,t2,t3;
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+
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+--echo # end of 10.2 tests
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+
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+--echo #
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--echo # MDEV-17518: Range optimization doesn't use ON expressions from nested outer joins
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--echo #
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create table t1(a int);
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diff --git a/mysql-test/main/join_outer_jcl6.result b/mysql-test/main/join_outer_jcl6.result
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index 2c7dc7b..2810ffa 100644
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--- a/mysql-test/main/join_outer_jcl6.result
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+++ b/mysql-test/main/join_outer_jcl6.result
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@@ -2694,6 +2694,46 @@ id timestamp modifiedBy id REV REVTYPE profile_id id REV person_id id REV
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DROP TABLE t1,t2,t3,t4;
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# end of 10.1 tests
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#
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+# MDEV-25362: name resolution for subqueries in ON expressions
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+#
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+create table t1 (a int, b int);
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+create table t2 (c int, d int);
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+create table t3 (e int, f int);
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+create table t4 (g int, h int);
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+explain
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+select *
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+from
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+t1 left join
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+(t2
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+join
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+t3 on
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+(t3.f=t1.a)
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+) on (t2.c=t1.a );
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+ERROR 42S22: Unknown column 't1.a' in 'on clause'
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+explain
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+select *
|
+from
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+t1 left join
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+(t2
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+join
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+t3 on
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+(t3.f=(select max(g) from t4 where t4.h=t1.a))
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+) on (t2.c=t1.a );
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+ERROR 42S22: Unknown column 't1.a' in 'where clause'
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+drop table t1,t2,t3,t4;
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+create table t1 (a int);
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+insert into t1 values (1),(2);
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+create table t2 (b int);
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+insert into t2 values (1),(2);
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+create table t3 (c int);
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+insert into t3 values (1),(2);
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+select * from ( select * from t1 left join t2
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+on b in (select x from t3 as sq1)
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+) as sq2;
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+ERROR 42S22: Unknown column 'x' in 'field list'
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+drop table t1,t2,t3;
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+# end of 10.2 tests
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+#
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# MDEV-17518: Range optimization doesn't use ON expressions from nested outer joins
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#
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create table t1(a int);
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diff --git a/sql/sql_derived.cc b/sql/sql_derived.cc
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index 500cb43..2ad31ae 100644
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--- a/sql/sql_derived.cc
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+++ b/sql/sql_derived.cc
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@@ -596,6 +596,32 @@ bool mysql_derived_init(THD *thd, LEX *lex, TABLE_LIST *derived)
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}
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|
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+ /*
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+ @brief
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+ Prevent name resolution out of context of ON expressions in derived tables
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+
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+ @param
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+ join_list list of tables used in from list of a derived
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+
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+ @details
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+ The function sets the Name_resolution_context::outer_context to NULL
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+ for all ON expressions contexts in the given join list. It does this
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+ recursively for all nested joins the list contains.
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+*/
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+
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+static void nullify_outer_context_for_on_clauses(List<TABLE_LIST>& join_list)
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+{
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+ List_iterator<TABLE_LIST> li(join_list);
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+ while (TABLE_LIST *table= li++)
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+ {
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+ if (table->on_context)
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+ table->on_context->outer_context= NULL;
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+ if (table->nested_join)
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+ nullify_outer_context_for_on_clauses(table->nested_join->join_list);
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+ }
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+}
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+
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+
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/*
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Create temporary table structure (but do not fill it)
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@@ -760,7 +786,12 @@ bool mysql_derived_prepare(THD *thd, LEX *lex, TABLE_LIST *derived)
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/* prevent name resolving out of derived table */
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for (SELECT_LEX *sl= first_select; sl; sl= sl->next_select())
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{
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+ // Prevent it for the WHERE clause
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sl->context.outer_context= 0;
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+
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+ // And for ON clauses, if there are any
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+ nullify_outer_context_for_on_clauses(*sl->join_list);
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+
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if (!derived->is_with_table_recursive_reference() ||
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(!derived->with->with_anchor &&
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!derived->with->is_with_prepared_anchor()))
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diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
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index ecde337..5338fad 100644
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--- a/sql/sql_lex.cc
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+++ b/sql/sql_lex.cc
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@@ -9391,7 +9391,7 @@ SELECT_LEX *LEX::parsed_subselect(SELECT_LEX_UNIT *unit)
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(curr_sel == NULL && current_select == &builtin_select));
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if (curr_sel)
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{
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- curr_sel->register_unit(unit, &curr_sel->context);
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+ curr_sel->register_unit(unit, context_stack.head());
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curr_sel->add_statistics(unit);
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}
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In brief: do not merge the changes from sql_parse.cc, add the change from the above diff to sql_lex.cc instead.
A fix for this bug was pushed into 10.2. The fix is good for 10.3 as well, but not for 10.4+. The tested diff for a fix good for 10.4+ is provided in a JIRA comment (see the result of testing in bb-10.4-igor). The difference between 10.2 and 10.4 fixes is minor (a couple of lines in one file).
http://lists.askmonty.org/pipermail/commits/2021-April/014539.html