update email selected from another table using the foreign key relation - sql

Question

I have 3 tables called Contact, APP_User, Customer Table. here I want to select email from my Contact table based on Contact_ID as Foreign key in App_User table and I want to Update the selected email into my Customer table based on App_User_Id as Foreign key in Customer table and primary key in APP_User Table.
Clearly:- I want to fetch email where Contact.contact_ID = APP_User.Contact_ID and Update the fetched email to Customer.emial where APP_User.App_User_Id = Customer.App_User_Id
UPDATE CRM.CRM_CUSTOMER_USER
SET EMAIL = (SELECT EMAIL
FROM QA29.ST_CONTACT
INNER JOIN QA29.ST_APP_USER ON QA29.ST_CONTACT.CONTACT_ID = 129)
WHERE APP_USER_ID = 120;
But it results in:
ORA-01427: single-row subquery returns more than one row

Answer 1

Join condition is missing in the inner query.
There must be multiple rows returned by the following query which is the cause of the issue:
SELECT
EMAIL
FROM
QA29.ST_CONTACT
INNER JOIN QA29.ST_APP_USER ON QA29.ST_CONTACT.CONTACT_ID = 129;
You must restrict this to single record using valid join condition, something like the following:
UPDATE CRM.CRM_CUSTOMER_USER
SET
EMAIL = (
SELECT
EMAIL
FROM
QA29.ST_CONTACT
INNER JOIN QA29.ST_APP_USER
ON QA29.ST_CONTACT.APP_USER_ID = QA29.ST_APP_USER.APP_USER_ID -- OR SOMETHING LIKE THIS
AND QA29.ST_CONTACT.CONTACT_ID = 129
)
WHERE
APP_USER_ID = 120;
Cheers!!