SQL query not returning all possible rows

I am writing a simple SQL query to get the latest records for every customerid. My SQL query –

SELECT sub.customerid, sub.device_count, sub.date_time FROM(
    SELECT customerid, cast(device_count as INT) as device_count, date_time,
        RANK() OVER
            (
                PARTITION by customerid
                ORDER BY date_time desc
            ) AS rownum 
    FROM tableA ) sub 
JOIN tableB d on sub.customerid = d.customerid 
WHERE rownum = 1 

Sample data:

customerid	device_count	date_time
A	3573	2021-07-26 02:15:09-05:00
A	4	2021-07-26 02:15:13-05:00
A	16988	2021-07-26 02:15:13-05:00
A	20696	2021-07-26 02:15:13-05:00
A	24655	2021-07-26 02:15:13-05:00
A	10000	2021-07-25 02:15:13-05:00
A	2000	2021-07-25 02:15:13-05:00

What I need is:

customerid	device_count	date_time
A	4	2021-07-26 02:15:13-05:00
A	16988	2021-07-26 02:15:13-05:00
A	20696	2021-07-26 02:15:13-05:00
A	24655	2021-07-26 02:15:13-05:00

But what I get after executing the above query is :

customerid	device_count	date_time
A	4	2021-07-26 02:15:13-05:00
A	16988	2021-07-26 02:15:13-05:00

I am not sure why the remaining rows are left out even though they have the same timestamp. Any help would be appreciated!

Answer

The timestamp might have milliseconds that you are are not seeing.

You can truncate to the nearest second:

SELECT sub.customerid, sub.device_count, sub.date_time
FROM (SELECT customerid, cast(device_count as INT) as device_count, date_time,
             RANK() OVER (PARTITION by customerid ORDER BY DATE_TRUNC(second, date_time) desc) AS rownum 
      FROM tableA
     ) sub JOIN
     tableB d 
     ON sub.customerid = d.customerid 
WHERE rownum = 1