Help with group by

Question

Can anyone tell why this query isn't working? It returns NOT a group by expression error. It has something to do with the subquery but I know I can't group by the alias of that statement. Any help would be appreciated.
SELECT acc.uprn,
NVL (SUM (lth.balance), 0) balance,
(SELECT SUM (balance)
FROM lsc_transaction_history lth
WHERE acc.account_no = lth.account_no
AND SUBSTR (lth.account_no,10,3) = 450) repair_balance
FROM lsc_occupants occ,
lsc_account acc,
lsc_area lmc,
hpm_view_property p,
lsc_account_parties_view accn,
lsc_transaction_history lth
WHERE occ.seq_no = acc.seq_no
AND acc.uprn = occ.uprn
AND occ.account_type = acc.account_type
AND lmc.code = acc.area_code
AND p.uprn = occ.uprn
AND accn.account_no = acc.account_no
AND lth.account_no = acc.account_no
GROUP BY acc.uprn

Answer 1

Well, the hints were already given, but maybe an example make it clearer.
SQL> create table lsc_account
  2  as
  3  select 1 uprn, '100000000000' account_no from dual union all
  4  select 1, '100000000450' from dual union all
  5  select 2, '100000000450' from dual
  6  /
Tabel is aangemaakt.
SQL> create table lsc_transaction_history
  2  as
  3  select '100000000000' account_no, 100 balance from dual union all
  4  select '100000000000', 200 from dual union all
  5  select '100000000000', 300 from dual union all
  6  select '100000000450', 400 from dual union all
  7  select '100000000450', 500 from dual
  8  /
Tabel is aangemaakt.
SQL> SELECT acc.uprn
  2       , NVL (SUM (lth.balance), 0) balance
  3       , ( SELECT SUM (balance)
  4             FROM lsc_transaction_history lth
  5            WHERE acc.account_no = lth.account_no
  6              AND SUBSTR (lth.account_no,10,3) = 450
  7         ) repair_balance
  8    FROM lsc_account acc
  9       , lsc_transaction_history lth
10   WHERE lth.account_no = acc.account_no
11   GROUP BY acc.uprn
12  /
          WHERE acc.account_no = lth.account_no
FOUT in regel 5:
.ORA-00979: Geen GROUP BY-uitdrukking.
SQL> select acc.uprn
  2       , nvl(sum(lth.balance),0) balance
  3       , nvl(sum(case substr(lth.account_no,10,3) when '450' then balance end),0) repair_balance
  4    from lsc_account acc
  5       , lsc_transaction_history lth
  6   where lth.account_no = acc.account_no
  7   group by acc.uprn
  8  /
UPRN      BALANCE REPAIR_BALANCE
   1         1500            900
   2          900            900You only need to access the lsc_transaction_history table once this way.
Regards,
Rob.