Finding updates in a table using Self-Join - sql

Question

I have a table as shown below
tablename - property
|runId|listingId|listingName
1 123 abc
1 234 def
2 123 abcd
2 567 ghi
2 234 defg
As you can see in above code there is a runId and there is a listing Id. I am trying to fetch for a particular runId which are the new listings added (In this case for runId 2 its 4th row with listing id 567 ) and which are the listing Ids that are update (In this case its row 3 and row 5 with listingId 123 and 234 respectively)
I am trying self join and it is working fairly for new updates but new additions are giving me trouble
SELECT p1.* FROM property p1
INNER JOIN property p2
ON p1.listingid = p2.listingid
WHERE p1.runid=456 AND p2.runid!=456
The above query provides me correct updated records in the table. But I am not able to find new listing. I used p1.listingid != p2.listingId , left outer join, still wont work.

Answer 1

I would use the ROW_NUMBER() analytical function for it.
SELECT
T.*
FROM
(
SELECT
T.*,
CASE
WHEN ROW_NUMBER() OVER(
PARTITION BY LISTINGID
ORDER BY
RUNID
) = 1 THEN 'INSERTED'
ELSE 'UPDATED'
END AS OPERATION_
FROM
PROPERTY
)
WHERE
RUNID = 2
-- AND OPERATION_ = 'INSERTED'
-- AND OPERATION_ = 'UPDATED'
This will provide the result as updated if listingid is added in any of the previous runid
Cheers!!

Answer 2

You may try this.
with cte as (
select row_number() over (partition by listingId order by runId) as Slno, * from property
)
select * from property where listingId not in (
select listingId from cte as c where slno>1
) --- for new listing added
with cte as (
select row_number() over (partition by listingId order by runId) as Slno, * from property
)
select * from property where listingId in (
select listingId from cte as c where slno>1
) --- for modified listing

Answer 3

For this, I would recommend exists and not exists. For updates:
select p.*
from property p
where exists (select 1
from property p2
where p2.listingid = p.listingid and
p2.runid < p.runid
);
If you want the result for a particular runid, add and runid = ? to the outer query.
And for new listings:
select p.*
from property p
where not exists (select 1
from property p2
where p2.listingid = p.listingid and
p2.runid < p.runid
);
With an index on property(listingid, runid), I would expect this to have somewhat better performance than a solution using window functions.
Here is a db<>fiddle.