single-row subquery returns more than one row - how to find the duplicate?

database, oracle, sql

Solution

Try with this query:

select applications.sap_sid, count(dr_option) 
from applications 
group by applications.sap_sid 
having count(dr_option) > 1

This should give you the sap_sid of the duplicated rows

Problem

iam not a big ORACLE - SQL Expert, so i hope someone knows a good way to find the "duplicate" record wich is causing the: single-row subquery returns more than one row error. This my Statement: ``` SELECT CAST(af.SAP_SID AS VARCHAR2(4000)) APP_ID, (SELECT DR_OPTION FROM DR_OPTIONS WHERE DR_OPTIONS.ID = ( select dr_option from applications where applications.sap_sid = af.sap_sid)) DR_OPTION FROM APPLICATIONS_FILER_VIEW af ``` it works on my test system, so iam "sure" there must be an error inside the available data records, but i have no idea how to find those ..

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