Pros:
- it is convenient to type and read numbers this way;
- Ada, Perl, C++, Go and Rust already support that;
- can support thousands as well as lakhs and crores;

Cons:
- standard SQL does not have this support;
- PostgreSQL treat `SELECT 1_000_000` as number one with `_000_000` alias: http://sqlfiddle.com/#!17/0a28f/400
- C++ has `1'000'000` instead of `1_000_000`;

What do you think?

{
    if (pos->type == TokenType::Asterisk)
    {
        ++pos;
        auto asterisk = std::make_shared<ASTAsterisk>();
        ParserColumnsTransformers transformers_p(allowed_transformers);
        ASTPtr transformer;
        while (transformers_p.parse(pos, transformer, expected))
        {
            asterisk->children.push_back(transformer);
        }
        node = asterisk;
        return true;
    }
    return false;
}
bool ParserQualifiedAsterisk::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)