Postgresql get some last rows from table

Question

I have PostgreSQL table:

Username1 SomeBytes1

Username2 SomeBytes1

Username1 SomeBytes1

Username1 SomeBytes1

I need to get some rows from with name Username1 but from the end of the table. For example i need last to rows with Username1

select from my_table where user = Username1 LIMIT 2

Gives me first 2 rows, but i need last two.

How can i select it?

Thank you.

Answer 1

first and last in a table is very arbitrary. In order to have a good predictable result you should always have an order by clause. And if you have that, then getting the last two rows will become easy.

For instance, if you have a primary key or something like an ID (which is populated by a sequence), then you can do:

select * from my_table where user = 'Username1' order by ID desc limit 2.

desc tells the database to sort the rows in reverse order, which means that last will be first.