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

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

ASTPtr alias_node;
    if (ParserAlias(allow_alias_without_as_keyword_now).parse(pos, alias_node, expected))
    {
        
        if (auto * ast_with_alias = dynamic_cast<ASTWithAlias *>(node.get()))
        {
            tryGetIdentifierNameInto(alias_node, ast_with_alias->alias);
        }
        else
        {
            expected.add(pos, "alias cannot be here");
            return false;
        }
    }
    return true;
}
bool ParserOrderByElement::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
{
    ParserExpressionWithOptionalAlias elem_p(false);
    ParserKeyword ascending("ASCENDING");
    ParserKeyword descending("DESCENDING");
    ParserKeyword asc("ASC");
    ParserKeyword desc("DESC");
    ParserKeyword nulls("NULLS");
    ParserKeyword first("FIRST");
    ParserKeyword last("LAST");
    ParserKeyword collate("COLLATE");
    ParserKeyword with_fill("WITH FILL");
    ParserKeyword from("FROM");
    ParserKeyword to("TO");