MYSQL Выбрать приоритетные данные, если они есть

Question

Мои текущие данные:

Month      Price A Price B  Status Approval

January    1000    2000      1        0
February   1000    2000      1        0
March      1000    2000      1        0
April      1000    2000      1        0
May        1000    2000      1        0
June       1000    2000      1        0
July       1000    2000      1        0
August     1000    2000      1        0  
September  1000    2000      1        0  
October    1000    3000      1        0   
October    2000    2000      2        0
October    3000    2000      2        1
November   1000    2000      1        0
December   1000    2000      1        0

*Status 1 = Not Changed, Status 2 = Changed, Approval 1 = Approved  

То, что я пытаюсь показать, это
, когда месяц> 1 (мой случай - октябрь),
ЕСЛИ STATUS = 2 AND APPROVAL = 1 ISNOT EXIST,
Показать данные с STATUS = 1 и APPROVAL = 0
ELSE SHOW STATUS = 2 AND APPROVAL = 1 При использовании group by
не работает, отображаются первые данные, если месяц больше 1

Мой запрос:

SELECT A.NAME AS MONTH, 
  IFNULL( B.PRICE_A, 0 ) PRICE_A,
  IFNULL( B.PRICE_B, 0 ) PRICE_B,
  STATUS,
  APPROVAL, 
FROM 
  REF_MONTH A
LEFT OUTER JOIN (
SELECT
    SUBSTR( PERIOD, '5,2' ) MONTH,
    ROUND( PRICE_A_FIX, 2 ) PRICE_A,
    ROUND( PRICE_B_FIX, 2 ) PRICE_B,
    A.STATUS,
    A.APPROVAL,
FROM
    PRICE_MONTH_LIST A
WHERE
    SUBSTR( PERIOD, 1, 4 ) = 2018 
) B ON B.MONRH= A.MONTH
WHERE DATE_FORMAT( STR_TO_DATE( CONCAT( 2018, month), '%Y%m' ), '%Y%m' ) <= 
DATE_FORMAT( SYSDATE( ), '%Y%m' )
GROUP BY A.MONTH
ORDER BY A.ID;

Мой ожидаемый результат:

Month      Price A Price B  Status Approval

January    1000    2000      1        0
February   1000    2000      1        0
March      1000    2000      1        0
April      1000    2000      1        0
May        1000    2000      1        0
June       1000    2000      1        0
July       1000    2000      1        0
August     1000    2000      1        0  
September  1000    2000      1        0  
October    3000    2000      2        1
November   1000    2000      1        0
December   1000    2000      1        0

Answer 1

Ниже был бы запрос -

with table1 as
(
  select 'January' as month, 1000 as priceA, 2000 as priceB, 1 as status, 0 as approval from dual
  union all
  select 'October' as month, 1000 as priceA, 3000 as priceB, 1 as status, 0 as approval from dual
  union all 
  select 'October' as month, 2000 as priceA, 2000 as priceB, 2 as status, 0 as approval from dual
  union all
  select 'October' as month, 3000 as priceA, 2000 as priceB, 2 as status, 1 as approval from dual
  )
,t1 as 
(
select month, count(*) as cnt, min(status) as min_status, 
max(status) max_status, min(approval) min_app, max(approval) max_app from table1
group by month
)
,t2 as 
(
select 
month,
case when cnt>1 and max_status<>2 and max_app<>1 then min_status else max_status end as status1,
case when cnt>1 and max_status<>2 and max_app<>1 then min_app else max_app end as approval1
from t1
)
select
t.month,
t.priceA,
t.priceB,
t.status,
t.approval
from table1 t
inner join t2 on t.month=t2.month and t.status=t2.status1 and t.approval=t2.approval1;

результат -

January 1000    2000    1   0
October 3000    2000    2   1

Поскольку не было никаких сценариев вставки, я использовал CTE с устным переводом db.

Надеюсь, это поможет.