Insert new rows based on conditions - Oracle SQL - sql

Question

I have a table:
table1
unique_id col_id col_nm col_val sequ
1 1 testq 1 100 1
1 2 testc 1 abc 1
1 1 testq 1 101 2
1 2 testc 1 xyz 2
1 5 test 5 10 1
1 8 test 6 100 1
2 1 testq 1 100 1
2 2 testc 1 pqr 1
2 1 testq 1 101 2
2 2 testc 1 xxy 2
2 5 test 5 qqw 1
2 8 test 6 100 1
I need to insert new rows in the table based on the following condition:
Find unique_id and sequ of col_id = 1 and col_nm = 'testq 1' and col_val = 100
Find col_val of col_id = 2 and col_nm = 'testc 1' and sequ = {sequ of step 1} and unique_id = {unique_id of step 1}.
Insert a new row for the corresponding unique_id, with col_id = 100, col_nm = 'test q100c', col_val = {col_val found in step 2}, sequ = {sequ found in step 2}
The output would be:
unique_id col_id col_nm col_val sequ
1 1 testq 1 100 1
1 2 testc 1 abc 1
1 1 testq 1 101 2
1 2 testc 1 xyz 2
1 5 test 5 10 1
1 8 test 6 100 1
1 100 test q100c abc 1
2 1 testq 1 100 2
2 2 testc 1 pqr 2
2 1 testq 1 101 2
2 2 testc 1 xxy 2
2 5 test 5 qqw 1
2 8 test 6 100 1
2 100 test q100c pqr 2
Is there anyway in SQL to achieve this?

Answer 1

We can use WITH clause in an INSERT … SELECT construct. So something like this?
insert into table1
with s1 as (
select t.unique_id
, t.sequ
from table1 t
where t.col_id = 1
and t.col_nm = 'testq 1'
and t.col_val = 100 )
, s2 as (
select s1.*
, t.col_val
from s1
join table1 t
on t.sequ = s1.sequ
and t.unique_id = s1.unique_id
where t.col_id = 2
and t.col_nm = 'testc 1'
)
select s2.unique_id
,100 as col_id
,'test q100c' as col_nm
,s2.col_val
,s2.sequ
from s2
/
I'm not sure I have entirely understood your rules - I used the col_val from step #2 (which is what your expected output shows) rather than the value from step #1 as your rule 3 states - but I hope this gives you a start. Also, this may not be a very efficient approach. I offer no guarantees regarding performance over a large volume of data.