complicated SQL: How to filter duplicate data about technical support and compute rank?

hi,
I have got a big problem. Could anyone give me a hand?

My first aim is:Remove the duplicate data, that is, the various entries of EndTime and Qos for a same ServiceID due to the repeated feedback. The rule is to only keep the records with the lowest Qos for a same ServiceID. If there are several records having the lowest Qos, then only keep whatever one of these records. The client accepts and prefers to this scheme. In this example, for the ID=6,7, and 8, just keep 6 or 7. And I have got answer of this aim here
SELECT MIN(Qos), serviceid, id, TCID, EndTime from service
GROUP BY serviceid

or SELECT DISTINCT serviceid,tcid,endtime,qos FROM (SELECT * FROM service ORDER BY serviceid, qos, id) AS base GROUP BY serviceid

aim2: Qos=1 represents the Satisfied Service. The monthly total Satisfied Services achieved by each technical support engineer is referred to as Personal Total Satisfied Services this Month. Those technical support engineers whose Personal Total Satisfied Service this Month ranking among the top 2 in that month are referred to as the Top 2 since this Month. If they are outstanding enough to be entitled to the Top 2 since this Month every month, then they can be referred to as Outstanding of Class 1. All in all, this step is to compute the Outstanding of Class 1. In this example, Top 2 since this Month for January is Andrew and Jacob, and that for February are Andrew, Dlyan, and Jacob. Therefore, the honor title of Outstanding of Class 1 is awarded to Andrew and Jacob.

please help me with aim2 (finally I should reach the aim 4, the final goal), result of aim 2 should be
TCID
Andrew
Jacob


explain:There are some technical service data (ServiceID, TCID, EndTime, and QoS) submitted by client in a whole year, and I have added a unique primary key (ID by name) because there are some duplicates.

some data:
ServiceID ID TCID EndTime Qos
2000 2 Jacob 2011/1/1 2
2000 3 Jacob 2011/1/1 2
2001 4 Jacob 2011/1/1 2
2002 5 Jacob 2011/2/3 1
2003 6 Tyler 2011/1/4 1

Data Structure:
ID: Unique primary key of record
ServiceID: ID of a certain service
TCID: ID of a technical support engineer
EndTime: Ending Time of aservice
Qos:Quality of service (1 Satisfied; 2 Average; 3Unsatisfactory/Dissatisfied).

DDL and insert SQL(mysql5):

CREATE TABLE `service` (
`ServiceID` INTEGER(11) NOT NULL,
`ID` INTEGER(11) NOT NULL ,
`TCID` VARCHAR(40) NOT NULL,
`EndTime` DATE NOT NULL,
`Qos` CHAR(1) NOT NULL,
PRIMARY KEY (`ID`),
UNIQUE KEY `ID` (`ID`)
);
COMMIT;
INSERT INTO `service` (`ServiceID`, `ID`, `TCID`, `EndTime`, `Qos`) VALUES
(2004, 9, 'Jacob', '2011-02-04', '1'),
(2000, 2, 'Jacob', '2011-01-01', '2'),
(2000, 3, 'Jacob', '2011-01-01', '2'),
(2001, 4, 'Jacob', '2011-01-01', '2'),
(2002, 5, 'Jacob', '2011-02-03', '1'),
(2003, 6, 'Tyler', '2011-01-04', '1'),
(2003, 7, 'Tyler', '2011-01-04', '1'),
(2003, 8, 'Tyler', '2011-01-03', '2'),
(2005, 10, 'Jacob', '2011-02-05', '1'),
(2006, 11, 'Jacob', '2011-02-04', '2'),
(2007, 12, 'Jacob', '2011-01-08', '1'),
(2008, 13, 'Tyler', '2011-02-06', '1'),
(2009, 14, 'Dylan', '2011-02-08', '1'),
(2010, 15, 'Dylan', '2011-02-09', '1'),
(2014, 16, 'Andrew', '2011-01-01', '1'),
(2013, 17, 'Andrew', '2011-01-01', '1'),
(2012, 18, 'Andrew', '2011-02-19', '1'),
(2011, 19, 'Andrew', '2011-02-02', '1'),
(2015, 20, 'Andrew', '2011-02-01', '1'),
(2016, 21, 'Andrew', '2011-01-19', '1'),
(2017, 22, 'Jacob', '2011-01-01', '1'),
(2018, 23, 'Dylan', '2011-02-03', '1'),
(2019, 24, 'Dylan', '2011-01-09', '1'),
(2020, 25, 'Dylan', '2011-01-01', '1'),
(2021, 26, 'Andrew', '2011-01-03', '1'),
(2021, 27, 'Dylan', '2011-01-11', '1'),
(2022, 28, 'Jacob', '2011-01-09', '1'),
(2023, 29, 'Tyler', '2011-01-19', '1'),
(2024, 30, 'Andrew', '2011-02-01', '1'),
(2025, 31, 'Dylan', '2011-02-03', '1'),
(2026, 32, 'Jacob', '2011-02-04', '1'),
(2027, 33, 'Tyler', '2011-02-09', '1'),
(2028, 34, 'Daniel', '2011-01-06', '1'),
(2029, 35, 'Daniel', '2011-02-01', '1');
COMMIT;

Almost forget to say that, just a reminder, the client only accept the SQL instead of stored procedure in database to implement it.

this is my first 2 aims, there are 2 more, I am intended to complete all these steps one after another. Could anyone help achieve the first goal? I know it is quite complicated and many thanks to you in advance.

aim3:Then, to compute the Outstanding of Class 2 (the engineers of Top 2 since this Month are not included) equals to compute those ranking the third and the forth places. In this example, the Outstanding of Class 2 is the Tyler.

aim4:The final goal is to combine the Outstanding of Class 1 with Outstanding of Class 2. The result will be ultimately transferred to report for rendering. My dataSet is just like:
TCID level
Andrew top2
Jacob top2
Tyler top4