To find changed data between two sql tables

Question

I have an issue in finding the changes between to tables.

I have a 2 discount files which i have uploaded to sql database using aws redshift.

I have to find the changes in both the tables. Which discount are changed for next month.

I have prepared the query but it brings all the columns from previous month as well.

My requirement is only changed data

I have created below query

(select * from imtest.aws_discount_new
minus
select * from imtest.aws_discount_prev)
UNION
(select * from imtest.aws_discount_prev
minus
select * from imtest.aws_discount_new);

But in this data from imtest.aws_discount_prev table which is not present in imtest.aws_discount_new are also included . which needs to be excluded

(select * from imtest.aws_discount_new
minus
select * from imtest.aws_discount_prev)
UNION
(select * from imtest.aws_discount_prev
minus
select * from imtest.aws_discount_new);

Expected : only new data from new file and data changed data prev file.

Answer 1

I think you only need the first part of your query:

select * from imtest.aws_discount_new
minus
select * from imtest.aws_discount_prev

This should get "new" records, which are not in "prev". That seems like a reasonable interpretation of what you want.