Subquery Inside Mega Query - oracle

Question

I have searched, but can find no example that fits what I need. Perhaps I am lost in the many joins of my query...
I am returning data from three Oracle 11g tables - ATE_TESTS, ATE_DATA, and TM_CONDITION_DYNAMIC. The query has other tables to join these. In fact, there are no less than 7 Joins.
ATE_DATA may have multiple records on the Many side of a join, but I want only the last-written row. ATE_DATA has an incremented Primary Key which I would like to use in the Aggregate Function MAX(DATA_PK) within a subquery. I think it should be in the WHERE clause of the main query, but I do not know how to implement this and there may be a better way.
Perhaps I might be educated?
My query is:
SELECT ate_serial, data_data, dyn_value
FROM ate_tests
LEFT JOIN ate_test_procedure
ON ate_tests.ate_pk = ate_test_procedure.proc_ate_test_fk
LEFT JOIN ate_test_data
ON ate_test_procedure.proc_pk = ate_test_data.data_ate_test_procedure_fk
LEFT JOIN tm_test_procedure
ON ate_test_procedure.proc_test_procedure = tm_test_procedure.proc_pk
LEFT JOIN tm_test_specification
ON ate_test_data.data_specification = tm_test_specification.spec_pk
LEFT JOIN tm_test_condition_dynamic
ON tm_test_specification.spec_condition_set_fk = tm_test_condition_dynamic.dyn_condition_set_fk
LEFT JOIN tm_test_sequences
ON ate_tests.ate_sequence_fk = tm_test_sequences.seq_pk
LEFT JOIN lu_tm_products_model
ON tm_test_sequences.seq_model = lu_tm_products_model.lumod_pk
WHERE upper(spec_name) = 'POWER'
AND lumod_model = 'AMP'
AND dyn_value = '136'
AND ate_yield = 1
AND upper(proc_procedure_name) = 'FINAL TEST'
AND proc_report = 1
AND proc_status = 1
ORDER BY ate_serial, dyn_value

Answer 1

... but I want only the last-written row.
It's typical top-n query. Let's say table a contains info about vegetables, table b their historical prices in different shops and s info about these shops. You are interested only in last price,
which you can find using the function row_number() (or max() ... keep dense rank last...).
with a as (select 1 vid, 'Tomato' name from dual union all
select 2 vid, 'Potato' name from dual union all
select 3 vid, 'Garlic' name from dual),
b as (select 1 pid, 1 vid, 1 sid, 11.5 price from dual union all
select 2 pid, 3 vid, 1 sid, 31.8 price from dual union all
select 3 pid, 1 vid, 1 sid, 13.2 price from dual union all
select 4 pid, 1 vid, 2 sid, 12.7 price from dual ),
s as (select 1 sid, 'Best Vegetables' name from dual union all
select 2 sid, 'Organic Products' name from dual)
select a.vid, a.name, s.name as shop, p.price as last_price
from a
left join (select vid, sid, price
from (select vid, sid, price,
row_number() over (partition by vid order by pid desc) rn
from b)
where rn = 1) p
on p.vid = a.vid
left join s on s.sid = p.sid
order by a.vid
Output:
VID Name Shop Price
--- -------- ------------------ -------
1 Tomato Organic Products 12.7
2 Potato
3 Garlic Best Vegetables 31.8