https://dev.mysql.com/doc/refman/8.0/en/arithmetic-functions.html

**Use case**
`a DIV b` - the same as `intDiv(a, b)`
`a MOD b` - the same as `modulo(a, b)`
else
                union_modes.push_back(ASTSelectWithUnionQuery::Mode::Unspecified);
            return true;
        }
        return false;
    };
    if (!parseUtil(pos, parse_element, parse_separator))
        return false;
    auto list = std::make_shared<ASTExpressionList>();
    list->children = std::move(elements);
    node = list;
    return true;
}
static bool parseOperator(IParser::Pos & pos, const char * op, Expected & expected)
{
    if (isWordCharASCII(*op))
    {
        return ParserKeyword(op).ignore(pos, expected);
    }
    else
    {
        if (strlen(op) == pos->size() && 0 == memcmp(op, pos->begin, pos->size()))
        {
            ++pos;
            return true;
        }
        return false;
    }
}
bool ParserLeftAssociativeBinaryOperatorList::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)