Selecting Max TimeStamp values for each ID within a Parameterized View - mysql

Question

MySQL version 5.5.49, on Linux Mint (Ubuntu 14.04.1 based)
The people table contains all of a family: Jed, David, Sarah, and Luke. The cars table contains the two cars we own. The CarPeople table contains an entry for each person who rides in a car, and contains keys that associate the personID to the carID. Last is the carData table, which contains the color of a car, a personID of someone who last painted the car, an image of the paint job, a date of the paint job, and a url to see the image.
This is a strange example, but the idea is that only people who are associated with specific car id's can paint or ride in the car. The example data I inserted has Jed (1) and David (2) riding together in car 1, while David (2), Luke (3), and Sarah (4) ride in car 2.
The following query result must be contained in a view, where a parameter is passed in which references the personID:
Show the CarID, ImageURL, and all people that ride with the PersonID, but only for the latest DataEntryTime for each CarID.
My people_concat column isn't outputting correct results, but I can fix that later.
My main issue is I can't figure out how to output the data row for the max dataentrytime for each carid within this view. Changes I have tried result in only one row being outputted, I can't figure out how to do this.
The crucial test query is this:
select c.* from (select #p1:=2 p) parm , carRiderList c;
This does a select from the view with respect to user 2, David. Instead of 5 rows, only two should be outputted, the first of CarID 2, and the first of carID 1.
Running these queries should result in one row, the one containg the highest dataentrytime for the associated personID's:
select c.* from (select #p1:=1 p) parm , carRiderList c;
select c.* from (select #p1:=3 p) parm , carRiderList c;
select c.* from (select #p1:=4 p) parm , carRiderList c;
Thank you!(SQL Code is below)
/* People in the database */
create table People
(
PersonID int(11) not null unique auto_increment,
phoneNumber varchar(30) not null unique,
Name varchar(40) not null unique,
PRIMARY KEY (PersonID)
)
ENGINE=InnoDB DEFAULT CHARSET=utf8;
insert into People (phoneNumber, Name)
values ("123-456-7891", "Jed"), ("223-456-7891", "David"), ("323-456-7891", "Luke"), ("423-456-7891", "Sarah");
select * from People;
/* Cars */
drop table if exists Cars;
create table Cars
(
CarID int(11) not null unique auto_increment,
PurchaseTime date,
PRIMARY KEY (CarID)
)
ENGINE=InnoDB DEFAULT CHARSET=utf8;
insert into Cars (PurchaseTime)
values ("2016-1-1"),("2016-1-2");
select * from Cars;
/* CarPerson: Will contain an entry for each person who rides in the car, and can paint it */
drop table if exists CarPerson;
create table CarPerson
(
CarPersonID int(11) not null unique auto_increment,
CarID int(11) not null,
CarRiderID int(11) not null,
PRIMARY KEY (CarPersonID),
FOREIGN KEY (CarID) references Cars(CarID),
FOREIGN KEY (CarRiderID) references People(PersonID)
)
ENGINE=InnoDB DEFAULT CHARSET=utf8;
insert into CarPerson(CarID, CarRiderID)
values (1, 1), (1, 2), (2, 2), (2, 3), (2, 4);
select * from CarPerson;
/* CarData: Contains CarID, the color was that car was painted, and the person who painted it, as well as a (fake) imageurl */
create table carData
(
DataID int(11) not null unique auto_increment,
CarID int(11) not null,
Color varchar(20),
DataEntryTime date,
PainterID int(11) not null,
ImageURL varchar(255),
PRIMARY KEY (DataID),
FOREIGN KEY (CarID) references Cars(CarID),
FOREIGN KEY (PainterID) references People(PersonID)
)
ENGINE=InnoDB DEFAULT CHARSET=utf8;
insert into carData(CarID, Color, DataEntryTime, PainterID, ImageURL)
values (1, "Blue", "2013-1-1", 1, "http://www.bluecivic.com"),
(1, "Green", "2013-1-2", 3, "http://greencivic.com"),
(2, "Red", "2014-1-3", 4, "http://redford.com"),
(2, "Purple", "2014-1-4", 2, "http://purpleford.com"),
(2, "Black","2014-1-5", 3, "http://blackford.com");
select * from carData;
/* View I am having trouble with */
create function p1() returns INTEGER DETERMINISTIC NO SQL return #p1;
drop view carRiderList;
create view carRiderList as
(select distinct cp.CarID, cd.ImageURL, DataEntryTime, (
select group_concat(Name order by CarID, PersonID = p1())from People p
left join CarPerson cp
on p.PersonID = cp.CarPersonID
where cp.CarID IN (
select distinct(CarID)
from CarPerson cp
where cp.CarPersonID = p1()
limit 1
)
)
as people_concat
from CarPerson cp
left join carData cd
on cd.CarID = cp.CarID
where cp.CarRiderID = p1()) order by DataEntryTime desc;
select c.* from (select #p1:=2 p) parm , carRiderList c;