More - Aggravation Over Aggregates

I have data that looks like this

create table #TestData
(clt_num int,
proc_cde varchar(10))
insert #TestData (clt_num,proc_cde)
select 1000, 'H0017' union all
select 2000, 'T1016' union all
select 2000, 'H0036' union all
select 2000, 'T0017' union all
select 3000, '99999' union all
select 3000, 'AAAAA' union all
select 3000, 'H0039'
select 4000, '99999' union all
select 5000, 'H0017' union all
select 5000, 'H0066' union all
select 100, 'H0036;TT' union all
select 200, 'T1016;XX' union all
select 200, 'H0036' union all
select 300, '99999;HH' union all
select 300, 'AAAAA' union all
select 400, '99999' union all
select 500, 'H0017;15' union all
select 500, 'H0036;XX'

I want to select records for a given clt_num based on weights (precedence) given to the different proc_cde(s). The rules for selecting the rows are:

If clt_num only has one row select that row

Select row that has the highest proc_cde by precedence for given clt_num

If clt_num has two or more rows but no proc_cde with an assigned precedence select both rows.
Note that there is a twist with the proc_cds in that they can have garbage at the end in the data records and I don't care about the garbage H0036, H1036;XX will have the same weight.

Therefore my expected results are:

clt_numproc_cde
100H0036;TT
200T1016;XX
30099999;HH
300AAAAA
40099999
500H0036;XX
1000H0017
2000T0017
300099999
3000AAAAA
400099999
5000H0039

In attempting to solve this problem I created a temp table called ProcCde_Weights:

create table #ProcCde_Weights
(proc_cde varchar(10),
weight int)
insert #ProcCde_Weights
(proc_cde,weight)
select 'H0039', 10 union all
select 'T1017', 20 union all
select 'T1016', 30 union all
select 'H0036', 40 union all
select 'T2011', 50 union all
select '90806', 60 union all
select '90862', 70 union all
select 'T1002', 80 union all
select 'H2031', 90 union all
select 'H2023', 100

And wrote this query:

select t.clt_num,
t.proc_cde,
case when p.weight is null then 1000
else p.weight
end as weight
from #TestData t left join #ProcCde_Weights p on t.clt_num = t.clt_num
and p.proc_cde = left(t.proc_cde,5)

which gives me this:

clt_numproc_cdeweight
1000H00171000
2000T101630
2000H003640
2000T00171000
3000999991000
3000AAAAA1000
4000999991000
5000H00171000
5000H00661000
100H0017;TT1000
200T101630
200H003640
30099999;HH1000
300AAAAA1000
400999991000
500H0017;151000
500H0036;XX40

… but now I need to modify the query with using the min function or max function (I think) to only select rows according to the rules I gave.

… and once again I seem to have a mental block when it comes to composing queries with aggregate functions.

Thanks in advance for any help.

Laurie

p.s. can anybody point me to any books or tutorials that can help me wrap my mind around aggregate functions.