[#MDEV-28573] View has to fail with error ER_SUBQUERY_NO_1

When the definition of view contains subselect with aggregation function COUNT() that returns more 1 row it has to fail with error ER_SUBQUERY_NO_1_ROW (1242) (or smth. like that ) but it doesn't

Test:

CREATE TABLE t1 (a INTEGER, b INTEGER);

CREATE TABLE t2 (x INTEGER);

INSERT INTO t1 VALUES (1,11), (2,22), (2,22);

INSERT INTO t2 VALUES (1), (2);

CREATE VIEW v1 AS SELECT (SELECT COUNT(b) FROM t2) FROM t1;

SELECT * from v1;

DROP VIEW v1;

DROP TABLES t1,t2;

Actual result:

(SELECT COUNT(b) FROM t2)

Using EXPLAIN EXTENDED it is seen the difference between:
original select:

EXPLAIN EXTENDED SELECT (SELECT COUNT(b) FROM t2) FROM t1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00

2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00

Warnings:

Note	1276	Field or reference 'test.t1.b' of SELECT #2 was resolved in SELECT #1

Note	1981	Aggregate function 'count()' of SELECT #2 belongs to SELECT #1

Note	1003	/* select#1 */ select <expr_cache><`test`.`t1`.`b`,count(`test`.`t1`.`b`),count(`test`.`t1`.`b`)>((/* select#2 */ select count(`test`.`t1`.`b`) from `test`.`t2`)) AS `(SELECT COUNT(b) FROM t2)` from `test`.`t1`

and select from view:

CREATE VIEW v1 AS SELECT (SELECT COUNT(b) FROM t2) FROM t1;

EXPLAIN EXTENDED  SELECT * from v1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00

3	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00

Warnings:

Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #2

Note	1003	/* select#1 */ select <expr_cache><`test`.`t1`.`b`>((/* select#3 */ select count(`test`.`t1`.`b`) from `test`.`t2`)) AS `(SELECT COUNT(b) FROM t2)` from `test`.`t1`

[MDEV-28573] View has to fail with error ER_SUBQUERY_NO_1_ROW (1242) but it doesn't Created: 2022-05-16 Updated: 2023-03-07 Resolved: 2023-03-07
Status:	Closed
Project:	MariaDB Server
Component/s:	Views
Affects Version/s:	10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9
Fix Version/s:	10.11.3, 11.0.2, 10.4.29, 10.5.20, 10.6.13, 10.8.8, 10.9.6, 10.10.4

[MDEV-28573] View has to fail with error ER_SUBQUERY_NO_1_ROW (1242) but it doesn't Created: 2022-05-16 Updated: 2023-03-07 Resolved: 2023-03-07