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

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

{
            ++pos;
            ParserStringLiteral parser_string_literal;
            ASTPtr ast_prefix_name;
            if (!parser_string_literal.parse(pos, ast_prefix_name, expected))
                return false;
            column_name_prefix = ast_prefix_name->as<ASTLiteral &>().value.get<const String &>();
        }
        if (with_open_round_bracket)
        {
            if (pos->type != TokenType::ClosingRoundBracket)
                return false;
            ++pos;
        }
        auto res = std::make_shared<ASTColumnsApplyTransformer>();
        res->func_name = getIdentifierName(func_name);
        res->parameters = expr_list_args;
        res->column_name_prefix = column_name_prefix;
        node = std::move(res);
        return true;
    }
    else if (allowed_transformers.isSet(ColumnTransformer::EXCEPT) && except.ignore(pos, expected))
    {
        if (strict.ignore(pos, expected))
            is_strict = true;
        ASTs identifiers;
        auto parse_id = [&identifiers, &pos, &expected]
        {
            ASTPtr identifier;
            if (!ParserIdentifier(true).parse(pos, identifier, expected))