Обновить записи на основе запроса выбора

Question

У меня есть таблица1:

u_a_id  d_c_s   c_nm    c_seq   r_c_p
1       908     Test1   1       20
10      908     Test1   1       21
11      908     Test1   1       12
12759   908     Test1   1       31
12759   908     Test1   1       32
12861   878     Test2   1       43
12861   878     Test2   1       44

У меня есть другая таблица2:

d_c_s   c_nm    c_seq   n_min_d_c_s     n_min_c_nm
908     Test1   1       12001           Test1, First
878     Test2   1       12002           Test2, First

Мне нужно обновить table1 ==>

• table1.c_nm = table2.n_min_c_nm
• table1.d_c_s = table2.n_min_d_c_s

Условие для обновления будет:

• ТОЛЬКО записи, где количество (u_a_id, d_c_s, c_seq)> 1 - select u_a_id, d_c_s, c_nm, c_seq, count(*) cnt from table1 where c_nm not in ('VOID', 'WRONG') group by u_a_id, d_c_s, c_nm, c_seq having count(*) > 1;
• table1.d_c_s = table2.d_c_s
• table1.c_nm = table2.c_nm
• table1.c_seq = table2.c_seq
• Использовать мин r_c_p

Вывод будет выглядеть так:

u_a_id  d_c_s   c_nm            c_seq   r_c_p
1       908     Test1           1       20
10      908     Test1           1       21
11      908     Test1           1       12
12759   12001   Test1, First    1       31
12759   908     Test1           1       32
12861   12002   Test2, First    1       43
12861   878     Test2           1       44

Как лучше всего создать запрос UPDATE / MERGE, чтобы это произошло?

DBFIDDLE DEMO - Ссылка

Answer 1

Вы можете использовать оператор MERGE для следующего:

MERGE INTO TABLE1 T1 
USING (
       SELECT
           MIN(TI1.R_C_P) AS R_C_P,
           TI1.U_A_ID,
           TI1.D_C_S,
           TI1.C_NM,
           TI1.C_SEQ,
           TI2.N_MIN_C_NM,
           TI2.N_MIN_D_C_S
       FROM
           TABLE1 TI1
           JOIN TABLE2 TI2 
           ON ( TI1.D_C_S = TI2.D_C_S
                AND TI1.C_NM = TI2.C_NM
                AND TI1.C_SEQ = TI2.C_SEQ
                AND TI1.C_NM NOT IN (
               'VOID',
               'WRONG'
           ) )
       GROUP BY
           TI1.U_A_ID,
           TI1.D_C_S,
           TI1.C_NM,
           TI1.C_SEQ,
           TI2.N_MIN_C_NM,
           TI2.N_MIN_D_C_S
       HAVING
           COUNT(1) > 1
   )
T2 ON ( T1.C_SEQ = T2.C_SEQ
        AND T1.R_C_P = T2.R_C_P )
WHEN MATCHED THEN 
UPDATE 
SET T1.C_NM = T2.N_MIN_C_NM,
T1.D_C_S = T2.N_MIN_D_C_S
WHERE
    T1.D_C_S = T2.D_C_S
    AND T1.C_NM = T2.C_NM 
    AND T1.U_A_ID = T2.U_A_ID -- ADDED THIS CONDITION
-- WHERE CONDITION IS USED AS IT CAN NOT BE USED INSIDE ON CLAUSE
-- TO AVOID ERROR : ORA-38104: Columns referenced in the ON Clause cannot be updated

Демонстрационная версия DB Fiddler

Ура !!

Answer 2

UPDATE table1 t1
SET t1.d_c_s =
(select 
t2.n_min_d_c_s
from
table2 t2
WHERE t1.d_c_s=t2.d_c_s
AND t1.c_nm=t2.c_nm
AND t1.c_seq=t2.c_seq),
t1.c_nm = 
(select 
t2.n_min_c_nm
from
table2 t2
WHERE t1.d_c_s=t2.d_c_s
AND t1.c_nm=t2.c_nm
AND t1.c_seq=t2.c_seq)

WHERE t1.r_c_p in (
SELECT min(r_c_p) min_r_c_p 
from table1
where c_nm not in ('VOID', 'WRONG') 
group by u_a_id, d_c_s, c_nm, c_seq 
having count(*) > 1
);

https://dbfiddle.uk/?rdbms=oracle_18&fiddle=870bca3d3cfb72e4638f678b9bf05199