Oracle update subquery of records - oracle

Question

I need to update a list of record given by a subquery, sniffing around on the web I tried this structure:
UPDATE
(
SELECT
a.COL1
FROM
TABLE1 a,
TABLE2 b
WHERE
a.field1 = b.field1
) update_tbl
SET
update_tbl.COL1 = 'VALUE'
But it returns to me this Oracle error:
-> ORA-01779: Cannot modify a column which maps to a non key-preserved table
My query is the following one:
UPDATE
(
SELECT
imp.*
FROM table1 imp
JOIN table2 sp ON imp.id_p = sp.id_p
JOIN table3 cs ON sp.id_s = cs.id_s
JOIN table4 cb ON cb.id_c = cs.id_c
WHERE
imp.id_b = cb.id_b
AND (
(to_char(imp.p,'yyyymm') < to_char(cb.data_in,'yyyymm')) OR
(cb.data_fi IS NOT NULL AND to_char(imp.p,'yyyymm') > to_char(cb.data_fi,'yyyymm'))
)
and (
(imp.v is not null) or
(imp.v_s is not null and imp.v_s <> 0) or
(imp.imp_co is not null and imp.imp_co <> 0) or
(imp.imp_acc is not null and imp.imp_acc <> 0)
)
) i
SET
i.v = null,
i.v_s = 0,
i.imp_co = 0,
i.imp_acc = 0,
i.ID_S_CONT = 'N',
i.ID_T_COMP = 'P',
i.date_upd = SYSDATE,
i.user_upd = 'SeR'
The subquery return 82 rows (tested now), and I do want to modify only that rows, What am I doing wrong?

Answer 1

I think you are updating to imp table. so you can try MERGE like below
MERGE INTO
IMP A
USING
( SELECT
imp.*
FROM table1 imp
JOIN table2 sp ON imp.id_p = sp.id_p
JOIN table3 cs ON sp.id_s = cs.id_s
JOIN table4 cb ON cb.id_c = cs.id_c
WHERE
imp.id_b = cb.id_b
AND (
(to_char(imp.p,'yyyymm') < to_char(cb.data_in,'yyyymm')) OR
(cb.data_fi IS NOT NULL AND to_char(imp.p,'yyyymm') >
to_char(cb.data_fi,'yyyymm'))
)
and (
(imp.v is not null) or
(imp.v_s is not null and imp.v_s <> 0) or
(imp.imp_co is not null and imp.imp_co <> 0) or
(imp.imp_acc is not null and imp.imp_acc <> 0)
)) B
ON (A.ID =B.ID)
WHEN MATCHED THEN
UPDATE SET
A.v = null,
A.v_s = 0,
A.imp_co = 0,
A.imp_acc = 0,
A.ID_S_CONT = 'N',
A.ID_T_COMP = 'P',
A.date_upd = SYSDATE,
A.user_upd = 'SeR'
Will update the table given by subquery. here A.ID =B.ID use the primary key.