CREATE DATABASE IF NOT EXISTS test;
DROP TABLE IF EXISTS test.one;
CREATE TABLE test.one(dummy UInt8) ENGINE = Memory;

SELECT x, t.name
    FROM (SELECT name, database AS x FROM system.tables) AS t
    ALL INNER JOIN (SELECT name AS x FROM system.databases) AS db USING x
    WHERE x = 'system' AND t.name = 'one'
    FORMAT PrettyCompactNoEscapes;

SELECT x, t.name
    FROM (SELECT name, database AS x FROM system.tables) AS t
    JOIN (SELECT name AS x FROM system.databases) AS db USING x
    WHERE x = 'system' AND t.name = 'one'
    SETTINGS join_default_strictness = 'ALL'
    FORMAT PrettyCompactNoEscapes;

SET join_default_strictness = 'ALL';

SELECT database, t.name
    FROM (SELECT * FROM system.tables) AS t
    JOIN (SELECT name, name AS database FROM system.databases) AS db USING database
    WHERE db.name = 'system' AND t.name = 'one'
    FORMAT PrettyCompactNoEscapes;

--SELECT db.name, t.name
--    FROM (SELECT name, database AS x FROM system.tables) AS t
--    JOIN (SELECT name AS x FROM system.databases) AS db USING x
--    WHERE x = 'system' AND t.name = 'one'
--    FORMAT PrettyCompactNoEscapes;

SELECT t.name --, db.name
    FROM (SELECT name, database FROM system.tables WHERE name = 'one') AS t
    JOIN (SELECT name FROM system.databases WHERE name = 'system') AS db ON t.database = db.name;

--SELECT db.name, t.name
--    FROM system.tables AS t
--    JOIN (SELECT * FROM system.databases WHERE name = 'system') AS db ON t.database = db.name
--    WHERE t.name = 'one';

SELECT database, t.name
    FROM system.tables AS t
    JOIN (SELECT name, name AS database FROM system.databases) AS db ON t.database = db.name
    WHERE t.name = 'one';

SELECT count(t.database)
    FROM (SELECT * FROM system.tables WHERE name = 'one') AS t
    JOIN system.databases AS db ON t.database = db.name;

--SELECT count(db.name)
--    FROM system.tables AS t
--    JOIN system.databases AS db ON t.database = db.name
--    WHERE t.name = 'one';

SELECT count()
    FROM system.tables AS t
    JOIN system.databases AS db ON db.name = t.database
    WHERE t.name = 'one';

DROP TABLE test.one;