Distinc on a subset of columns

Question

Hi, I have a query working such as:
selec distinct t1.col1, t2.col1, t2.col2, t3.col1
from table1 t1, table2 t2, table3 t3
where t1.some_id = t2.some_id and t2.some_val = t3.some_val
order by t1.col1
This goes through some code that outputs the same query but it adds some fields at the begining of the select statement (select count(1) over () fq_reserved_total_cnt,), this causes my query to not work anymore since the distinct is moved from the first row.. without changing the code (the prefix bolded), how can i fix this distinct issue? the query takes a while to run given that i actually have more tables so i'm looking for a solution that won't impact run time that much.
select count(1) over () fq_reserved_total_cnt, distinct t1.col1, t2.col1, t2.col2, t3.col1
from table1 t1, table2 t2, table3 t3
where t1.some_id = t2.some_id and t2.some_val = t3.some_val
order by t1.col1
Thanks,

Answer 1

If ,
select count(1) over () fq_reserved_total_cnt, distinct t1.col1, t2.col1, t2.col2, t3.col1 
from table1 t1, table2 t2, table3 t3 
where t1.some_id = t2.some_id and t2.some_val = t3.some_val 
order by t1.col1
is your original query, can the below query,
select count(1) over () fq_reserved_total_cnt, distinct t1.col1, t2.col1, t2.col2, t3.col1 
from table1 t1, table2 t2, table3 t3 
where t1.some_id = t2.some_id and t2.some_val = t3.some_val 
order by t1.col1
be tweaked as
select distinct  col1_t1, col1_t2, col2_t2, col1_t3
from(
select count(1) over () fq_reserved_total_cnt, distinct t1.col1 col1_t1, t2.col1 col1_t2, t2.col2 col2_t2, t3.col1  col1_t3
from table1 t1, table2 t2, table3 t3 
where t1.some_id = t2.some_id and t2.some_val = t3.some_val 
order by t1.col1
Thanks,
Vivek