Question

I have table from which I am fetching records for two time interval as written below.

Query1:

select distinct(Id) 
from dbo.tableA 
where datediff(hour, dtCreate, getdate()) < 24

Query2:
select distinct(Id) 
from dbo.tableA 
where datediff(hour, dtCreate, getdate()) < 48
and datediff(hour, dtCreate, getdate()) > 24

The query1 returns 50 records and query2 returns 45 records.
After this I want to find those records which which are not present in query2 but present in query1. Can anybody suggest me how to do this?? Thanks in advance.

Answer 1

Use the EXCEPT keyword:

SELECT Id
  FROM dbo.tableA
 WHERE datediff(hour, dtCreate, getdate()) < 24
EXCEPT
SELECT Id
  FROM dbo.tableA
 WHERE datediff(hour, dtCreate, getdate()) < 48
  AND datediff(hour, dtCreate, getdate()) > 24
;

(Note: I got rid of the DISTINCTs, because EXCEPT does that implicitly; but if you prefer to leave the DISTINCTs in there, for clarity’s sake, you absolutely can.)