SQL Oracle Update containing left join - sql

Question

I want to perform an update for the results of a select query.
SELECT
a.reason,
n.note
FROM applications a
LEFT JOIN notes n on n.app_id = a.app_id
AND n.note LIKE '%old%'
WHERE a.code = 'run' AND a.reason IS NULL
I thought I could perform these updates separately wrapping the select in an update however I get the error ORA-01733: virtual column not allowed here. How can I go about performing these updates?
UPDATE (
SELECT
a.reason AS Reason
FROM applications a
LEFT JOIN notes n on n.app_id = a.app_id
AND n.note LIKE '%old%'
WHERE a.code = 'run' AND a.reason IS NULL
) SET Reason = null
UPDATE (
SELECT
n.note AS Note
FROM applications a
LEFT JOIN notes n on n.app_id = a.app_id
AND n.note LIKE '%old%'
WHERE a.code = 'run' AND a.reason IS NULL
) SET Note = null

Answer 1

You can't update the two tables at the same time. You need two different update statements as follows:
Updating the APPLICATIONS table is quite easy as all the records of the APPLICATIONS table having a.code = 'run' AND a.reason IS NULL will be there in your SELECT query.
UPDATE APPLICATIONS A
SET
REASON = NULL
WHERE A.CODE = 'run'
AND A.REASON IS NULL;
To update the NOTES table, you can use the EXISTS clause as follows:
UPDATE NOTES N
SET
NOTE = NULL
WHERE EXISTS (
SELECT 1
FROM APPLICATIONS A
WHERE N.APP_ID = A.APP_ID
AND A.CODE = 'run'
AND A.REASON IS NULL
)
AND N.NOTE LIKE '%old%'
You must update the NOTES table first and then APPLICATIONS table as while updating the NOTES table you are using the condition A. REASON IS NULL but while updating the APPLICATIONS table, you are updating the REASON column.