**Usage**
Postgres, MySQL, and Oracle support the expression `LEFT JOIN ... ON 1 = 1`, but ClickHouse does not.

It may be possible to replace `LEFT JOIN ... ON 1 = 1` with `CROSS JOIN`, but I want to use the query in the same form for lots of databases.

Please support the expression `LEFT JOIN ... ON 1 = 1`.


**Detailed SQL**
```SQL
CREATE TABLE test
(
    `name` Nullable(String),
    `id` int
)
ENGINE = Log();

insert into test values ('a', 1) ('b', 2) (null, 3);

select * from test t1 left join (select * from test ) t2 on 1 = 1   
-- DB::Exception: Not equi-join ON expression: 1 = 1. No columns in one of equality side.: While processing 1 = 1.
```

{
    Names key_names_right = getAllNames(JoinTableSide::Right);
    NameSet required_columns_set(key_names_right.begin(), key_names_right.end());
    for (const auto & joined_column : columns_added_by_join)
        required_columns_set.insert(joined_column.name);
    return Names(required_columns_set.begin(), required_columns_set.end());
}
NameSet TableJoin::requiredRightKeys() const
{
    NameSet required;
    forAllKeys<RightSideTag>(clauses, [this, &required](const auto & name)
    {
        auto rename = renamedRightColumnName(name);
        for (const auto & column : columns_added_by_join)
            if (rename == column.name)
                required.insert(name);
        return true;
    });
    return required;
}
NamesWithAliases TableJoin::getRequiredColumns(const Block & sample, const Names & action_required_columns) const