Oracle unexpected sorting behaviour - sql

Question

Consider the Following:
CREATE TABLE TestPersons
(
PersonID int,
Name varchar(255),
FirstName varchar(255),
Address varchar(255)
)
insert into TestPersons(PersonID, Name, FirstName , Address) Values (1, 'name1', 'firstname1', 'adress1');
insert into TestPersons(PersonID, Name, FirstName , Address) Values (2, 'name2', 'firstname2', 'adress2');
insert into TestPersons(PersonID, Name, FirstName , Address) Values (3, 'name3', 'firstname3', 'adress3');
insert into TestPersons(PersonID, Name, FirstName , Address) Values (4, 'name4', 'firstname4', 'adress4');
First Query (works fine):
SELECT name, firstname, personid, count(name), row_number() over (ORDER BY name, firstname) as rn
FROM testpersons
GROUP BY name, firstname, personid
returns:
name1 firstname1 1 1 1
name2 firstname2 2 1 2
name3 firstname3 3 1 3
name4 firstname4 4 1 4
Second Query (unexpected result):
SELECT name, firstname, personid, count(name), row_number() over (ORDER BY name desc, firstname desc) as rn
FROM testpersons
GROUP BY name, firstname, personid
returns for all rows name4 and firstname4:
name4 firstname4 4 1 1
name4 firstname4 3 1 2
name4 firstname4 2 1 3
name4 firstname4 1 1 4
I would expect a changed order of the result from the first query.
Any Idea why is that?
Output of select * from v$version is as follows:
Oracle Database 12c Release 12.1.0.1.0 - 64bit Production 0
PL/SQL Release 12.1.0.1.0 - Production 0
"CORE 12.1.0.1.0 Production" 0
TNS for 64-bit Windows: Version 12.1.0.1.0 - Production 0
NLSRTL Version 12.1.0.1.0 - Production 0

Answer 1

I don't know what you are talking about. Below is a direct copy and paste from my session where I entered the commands as you posted them. I get the correct result from the second query.
Is there something you didn't tell us? What version of Oracle are you using? How are you interacting with it? What is your front-end? Do you send your queries directly or through some app?
What you see below is Oracle 11.2 XE, SQL*Plus front-end.
SQL> CREATE TABLE TestPersons
2 (
3 PersonID int,
4 Name varchar(255),
5 FirstName varchar(255),
6 Address varchar(255)
7 );
Table created.
SQL> insert into TestPersons(PersonID, Name, FirstName , Address) Values (1, 'name1', 'firstname1', 'adress1');
1 row created.
SQL> insert into TestPersons(PersonID, Name, FirstName , Address) Values (2, 'name2', 'firstname2', 'adress2');
1 row created.
SQL> insert into TestPersons(PersonID, Name, FirstName , Address) Values (3, 'name3', 'firstname3', 'adress3');
1 row created.
SQL> insert into TestPersons(PersonID, Name, FirstName , Address) Values (4, 'name4', 'firstname4', 'adress4');
1 row created.
SQL> column name format a10
SQL> column firstname format a18
SQL> SELECT name, firstname, personid, count(name), row_number() over (ORDER BY name, firstname) as rn
2 FROM testpersons
3 GROUP BY name, firstname, personid;
NAME FIRSTNAME PERSONID COUNT(NAME) RN
---------- ------------------ ---------- ----------- ----------
name1 firstname1 1 1 1
name2 firstname2 2 1 2
name3 firstname3 3 1 3
name4 firstname4 4 1 4
4 rows selected.
SQL> SELECT name, firstname, personid, count(name), row_number() over (ORDER BY name desc, firstname desc) as rn
2 FROM testpersons
3 GROUP BY name, firstname, personid;
NAME FIRSTNAME PERSONID COUNT(NAME) RN
---------- ------------------ ---------- ----------- ----------
name4 firstname4 4 1 1
name3 firstname3 3 1 2
name2 firstname2 2 1 3
name1 firstname1 1 1 4
4 rows selected.