Find records that do not exist in 2nd table, and also the values mapped against them from first

Hi so this question has been asked before, but I am not only just trying to extract the records that do not just exist in the first table, but also the mapping from the first table where they don’t?

Eg.

Assuming I will join using Month and Year–

Table 1:

Month	Year
3	2021
4	2021
5	2021
6	2023

Table 2:

ID	Month	Year
11	3	2021
22	4	2021
33	5	2021

Output:

ID	Month	Year
11	6	2023
22	6	2023
33	6	2023

Answer

From what you say and show, you want to cross join all table 2 rows to the table 1 rows that don’t have a match in table 2. For the lookup you can use NOT EXISTS.

select t2.id, t1.month, t1.year
from t1 cross join t2
where not exists
(
  select null
  from t2
  where t2.year = t1.year and t2.month = t1.month
);