Oracle 18c

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

CREATE TABLE EXAMPLE(
EVENT_ID NUMBER,
NUM_A NUMBER,
NUM_A_SRC VARCHAR2(10),
NUM_B NUMBER,
NUM_B_SRC VARCHAR2(10)
); 
INSERT INTO EXAMPLE (EVENT_ID, NUM_A, NUM_A_SRC, NUM_B, NUM_B_SRC)
VALUES
(1, 5, 'Yelp', 4, 'Google');

1 rows affected

INSERT INTO EXAMPLE (EVENT_ID, NUM_A, NUM_A_SRC, NUM_B, NUM_B_SRC)
VALUES
(2, 3, 'Yelp', 1, 'Google');
1 rows affected

select event_id, num_a_src src, num_a rnk from example
union all
select event_id, num_b_src, num_b from example


EVENT_ID
SRC
RNK


1
Yelp
5

2
Yelp
3

1
Google
4

2
Google
1