**Use case**
`SELECT POSITION('/' IN s) FROM (SELECT 'Hello/World' AS s);`

The same as `position(s, '/')`

}
        }
    }
    else if (mode == TTLMode::DELETE && s_where.ignore(pos))
    {
        if (!parser_exp.parse(pos, where_expr, expected))
            return false;
    }
    else if (mode == TTLMode::RECOMPRESS)
    {
        if (!s_codec.ignore(pos))
            return false;
        if (!parser_codec.parse(pos, recompression_codec, expected))
            return false;
    }
    auto ttl_element = std::make_shared<ASTTTLElement>(mode, destination_type, destination_name);
    ttl_element->setTTL(std::move(ttl_expr));
    if (where_expr)
        ttl_element->setWhere(std::move(where_expr));
    if (mode == TTLMode::GROUP_BY)
    {
        ttl_element->group_by_key = std::move(ast_group_by_key->children);
        ttl_element->group_by_aggregations = std::move(group_by_aggregations);
    }
    if (mode == TTLMode::RECOMPRESS)
        ttl_element->recompression_codec = recompression_codec;
    node = ttl_element;
    return true;
}
bool ParserIdentifierWithOptionalParameters::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)