ORA-01427: single-row subquery returns more than one row

The error ORA-01427 is raised, when a sub-query returns more than one row to an Equality or in-Equality operator.

The reason being there are restrictions on the legal comparison operators.The single row subquery operator are

Symbol	Meaning
=	equal
>	greater than
>=	greater than or equal
<	less than
<=	less than or equal
<>	not equal
!=	not equal

So whenever you are using these single row subquery operator, if you return more than one row,it will start throwing the error

How to resolve the error ORA-01427

(1) either we change the query to use Multiple -row Subquery Operators 

Multiple-row Sub-query Operators
Symbol	Meaning
IN	equal to any member in a list
NOT IN	not equal to any member in a list
ANY	returns rows that match any value on a list
ALL	returns rows that match all the values in a list

(2) We look at the query and find out what is happening, why it is returning more rows than expected. Like the way we resolved this error for Concurrent Manager issue. It is generally advisable  use the sub-query based on primary key in order to get consistent result,

Lets us take a look at few example

Few Examples

(1) While starting the concurrent Manager in the EBS environment, we were getting below error

Cause: cleanup_node failed due to ORA-01427: single-row subquery returns more than one row
ORA-06512: at "APPS.FND_CP_FNDSM", line 29
ORA-06512: at line 1.

This error happens when we have more than two FNDSM of FNDIM defined for the node.So we selected the node name of all the concurrent Manager in the system

Solution
We can resolve the solution manually through below update

SQL> select CONCURRENT_QUEUE_NAME,NODE_NAME from fnd_concurrent_queues group by CONCURRENT_QUEUE_NAME,NODE_NAME;

CONCURRENT_QUEUE_NAME	NODE_NAME
FNDSCH	SUNTEST
PODAMGR	SUNTEST
FTE_TXN_MANAGER	SUNTEST
FNDSM_20151_SUNTEST	SUNTEST
FNDICM	SUNTEST
FNDTMTST	SUNTEST
STANDARD	SUNTEST
FNDIM_SUNTEST	SUNTEST
FNDIM_20153_SUNTEST	SUNTEST
WFMLRSVC	SUNTEST
XDP_Q_FE_READY_SVC	SUNTEST
WMSTAMGR	SUNTEST
INVMGR	SUNTEST
AMSDMIN	SUNTEST
FNDSM_SUNTEST	SUNTEST

We can see there are two FNDSM and FNDIM for the node SUNTEST.

FNDSM_20151_SUNTEST SUNTEST
FNDIM_SUNTEST SUNTEST
FNDIM_20153_SUNTEST SUNTEST
FNDSM_SUNTEST SUNTEST

Lets do the update now

SQL> update fnd_concurrent_queues set NODE_NAME=null where CONCURRENT_QUEUE_NAME='FNDSM_20151_SUNTEST';
1 row updated.
SQL> update fnd_concurrent_queues set NODE_NAME=null where CONCURRENT_QUEUE_NAME='FNDIM_20153_SUNTEST';
1 row updated.
SQL> commit;
Commit complete.

SQL> select CONCURRENT_QUEUE_NAME,NODE_NAME from fnd_concurrent_queues group by CONCURRENT_QUEUE_NAME,NODE_NAME;

CONCURRENT_QUEUE_NAME	NODE_NAME
FNDSCH	SUNTEST
PODAMGR	SUNTEST
FTE_TXN_MANAGER	SUNTEST
FNDSM_20151_SUNTEST
FNDICM	SUNTEST
FNDTMTST	SUNTEST
STANDARD	SUNTEST
FNDIM_SUNTEST	SUNTEST
FNDIM_20153_SUNTEST
WFMLRSVC	SUNTEST
XDP_Q_FE_READY_SVC	SUNTEST
WMSTAMGR	SUNTEST
INVMGR	SUNTEST
AMSDMIN	SUNTEST
FNDSM_SUNTEST	SUNTEST

Or we can run conc clean and run autoconfig again to resolve the issue

SQL> EXEC FND_CONC_CLONE.SETUP_CLEAN;
COMMIT;
EXIT;

(2) Another example would be

SELECT * FROM employers
WHERE dept_id = (SELECT dept_id
FROM dept);

This will fail as we are selecting all dept_id in subquery while expecting one. This will succeed if dept is having one rows only. To resolve we need to add some where clause in subquery so that it returns one value

SELECT * FROM employers
WHERE dept_id = (SELECT dept_id
FROM dept where location='NEWYORK');

or

We can put in operator in place of equality operator

SELECT * FROM employers
WHERE dept_id in (SELECT dept_id
FROM dept);

I hope you this content on ORA-01427: single-row subquery returns more than one row. Please do provide feedback

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