Details
Blocker Description
Outside references in LEFT JOIN's ON expression produce "unknown column" error.
Create the test dataset (As far as I'm aware, there's nothing special about this choice of tables/columns):
create table t10 ( |
pk int primary key, |
a int |
);
|
insert into t10 values (1,1); |
 |
create table t11 ( |
pk int primary key, |
b int |
);
|
create table t12 (a int); |
insert into t12 values (1),(2); |
Run the query Q1:
select
|
a,
|
(select count(*) |
from |
t10 left join t11 on t11.pk=t12.a |
where |
t10.pk=1
|
) as SUBQ |
from t12; |
ERROR 1054 (42S22): Unknown column 't12.a' in 'on clause'
|
Wrapping the outside reference in a subquery helps: Q2:
select
|
a,
|
(select count(*) |
from |
t10 left join t11 on t11.pk=(select t12.a from dual) |
where |
t10.pk=1
|
) as SUBQ |
from t12; |
+------+------+
|
| a | SUBQ |
|
+------+------+
|
| 1 | 1 |
|
| 2 | 1 |
|
+------+------+
|
I've tried Q1 on MySQL 8.0.22 or PostgreSQL and it worked in both.
Is it a bug MariaDB produces this error?