Why Oracle is saying not a GROUP BY expression?

Question

I am Trying to retrive data from the Oracle database table with following conditions

1. All entries found by zip-code should be grouped, sorted by zip-code desce

Answer 1

The specific answer to your question is that uuid is not included in the group by expression. Other answers have already explained the MySQL (mis) feature that allows this to happen. Fixing the query is easy:

SELECT ba.uuid AS uuid, COUNT(*) over() AS rowcount
FROM basicaddress ba 
WHERE ba.postalcode='143456' OR ba.lastname LIKE '%143456%' OR ba.city LIKE '%143456%'
GROUP BY uuid,
        CASE WHEN ba.postalcode='143456' THEN ba.postalcode END 
ORDER BY 
        max(CASE WHEN ba.postalcode='143456' THEN ba.postalcode END) DESC, 
        max(CASE WHEN ba.lastname LIKE '%143456%' THEN ba.lastname END) ASC, 
        max(CASE WHEN ba.city LIKE '%143456%' THEN ba.city ELSE ba.postalcode END)

I also removed the "distinct" which should be redundant when using group by.

That said, I don't see how this satisfies your original question. I would expect something more along the lines of the following:

select (case when postalcode is not null then postalcode
             when city is not null then city
             when lastname is not null then lastname
        end),
       (case when postalcode is not null then 1
             when city is not null then 2
             when lastname is not null then 3
        end),
       count(*)
from basicaddress ba
group by (case when postalcode is not null then postalcode
               when city is not null then city
               when lastname is not null then lastname
          end),
         (case when postalcode is not null then 1
             when city is not null then 2
             when lastname is not null then 3
        end)
order by 1, 2

This may not be exactly what you need, but it should point you in the right direction. Also, this is standard SQL and will work in both databases.