How to get the last row of an Oracle a table

Solution 1:

There is no such thing as the "last" row in a table, as an Oracle table has no concept of order.

However, assuming that you wanted to find the last inserted primary key and that this primary key is an incrementing number, you could do something like this:

select *
  from ( select a.*, max(pk) over () as max_pk
           from my_table a
                )
 where pk = max_pk

If you have the date that each row was created this would become, if the column is named created:

select *
  from ( select a.*, max(created) over () as max_created
           from my_table a
                )
 where created = max_created

Alternatively, you can use an aggregate query, for example:

select *
  from my_table
 where pk = ( select max(pk) from my_table )

Here's a little SQL Fiddle to demonstrate.

Solution 2:

SELECT * FROM (
    SELECT * FROM table_name ORDER BY sortable_column DESC
) WHERE ROWNUM = 1;

Solution 3:

select * from table_name ORDER BY primary_id DESC FETCH FIRST 1 ROWS ONLY;

That's the simplest one without doing sub queries

Solution 4:

The last row according to a strict total order over composite key K(k1, ..., kn):

SELECT  *
FROM    TableX AS o
WHERE   NOT EXISTS (
            SELECT  *
            FROM    TableX AS i
            WHERE   i.k1 > o.k1
                OR  (i.k1 = o.k1 AND i.k2 > o.k2)
                ...
                OR  (i.k1 = o.k1 AND i.k2 = o.k2 AND i.k3 = o.k3 AND ... AND i.kn > o.kn)
        )
;

Given the special case where K is simple (i.e. not composite), the above is shortened to:

SELECT  *
FROM    TableX AS o
WHERE   NOT EXISTS (
            SELECT  *
            FROM    TableX AS i
            WHERE   i.k1 > o.k1
        )
;

Note that for this query to return just one row the key must order without ties. If ties are allowed, this query will return all the rows tied with the greatest key.