SQL & PL/SQL :: Create Multiple Records Based On Condition

CREATE TABLE test1
(strt_num NUMBER ,
end_num NUMBER ,
des VARCHAR2(5),
CONSTRAINT pk_strt_num PRIMARY KEY (strt_num)
);
INSERT INTO test1 VALUES (5, 8, 'GC');
INSERT INTO test1 VALUES (10, 25, 'AB');
INSERT INTO test1 VALUES (12, 35, 'PC');
INSERT INTO test1 VALUES (22, 65, 'LJ');

SELECT * FROM test1

STRT_NUM END_NUM DES
-------------- ------------ -------------
5 8 GC
10 25 AB
12 35 PC
22 65 LJ

The requirement is the records should be split based on below conditions

1. Split only those records WHERE (end_num - strt_num) > 10
2. If TRUNC((end_num - strt_num)/10) = n, then n + 1 number of rows should be created for that record
3. While splitting the records,
-> For first record , START_NUM = Original STRT_NUM and END_NUM = START_NUM + 10
-> Second record , STRT_NUM = previous END_NUM + 1 and END_NUM = previous END_NUM + 10
And this should continue for all records except the last record
-> For last record, STRT_NUM = previous END_NUM + 1 AND END_NUM = Original END_NUM

This table has 5 million records. Only for 2000 records (end_num - strt_num) > 10.

Expected Output.

STRT_NUM END_NUM DES
------------- -------- ---------
5 8 GC -- No chage, END_NUM - STRT_NUM < 10

10 20 AB
21 25 AB

12 22 PC
23 32 PC
33 35 PC

22 32 LJ -- STRT_NUM = Original STRT_NUm, END_NUM = STRT_NUM + 10
33 42 LJ -- STRT_NUM = Previous END_NUM + 1, END_NUM = previous END_NUM + 10
43 52 LJ -- STRT_NUM = Previous END_NUM + 1, END_NUM = previous END_NUM + 10
53 62 LJ -- STRT_NUM = Previous END_NUM + 1, END_NUM = previous END_NUM + 10
63 65 LJ -- STRT_NUM = Previous END_NUM + 1, END_NUM = Original END_NUM