Access the last entrys in the database with a java program

Question

I am currently writing a Java program.

Brief description of the component:

I have an "Entries" table. This table has the following columns: Date (which is entered automatically when the user makes a double entry) Input (This is the double number from the user)

With 5 entries, for example, the program should now access the last 2 entries made by the user and reflect them in the program.

For example, the table looks like this:

Date --------- Entry

21.01.2022 -- 500

01.03.2022 -- 551

04.05.2022 -- 629

30.06.2022 -- 701

15.07.2022 -- 781

Then the program should give me the 701 and the 781.

What is the most sensible way to do this? It makes no sense to use the following "SQL statement": Select where date 06/30/2022 because it is no longer useful when the user makes a new entry.

Please help!!

Answer 1

You can use the following SQL statement to select the last two rows:

select * from Entries order by date desc limit 2;

Answer 2

select Entry
  from your_table
 order by date desc -- show most recent entries above in the results
 fetch first 2 rows only; -- show first 2 records only

You might be running on an old DB (version less than 12) so "fetch" might not be introduced.

Try this then

select * 
  from (select Entry
          from your_table
         order by date desc)
 where rownum <= 2;

Answering to your question how to get a penultimate value

select * 
  from (select Entry, row_number() over(order by date_col desc) rn
          from your_table)
 where rn = 2;

the "rn = 2" condition will get you not the last date but a date before the last. Setting it to 1 will get you the row with most recent date