SQL Developer

Hi,

I dont know why DBA_TAB_COLUMNS shows duplicate columns on some databases. Though columns are just 18 but it shows 24 columns. Please help.

SELECT distinct column_name,column_id FROM all_tab_columns WHERE table_name = 'T$NATIVE_REDACTIONS' ORDER BY column_id;


COLUMN_NAME | COLUMN_ID
------------------------------| ----------
NATIVE_REDACTIONID | 1
DOCUMENTID | 2
AID_USERID | 3
AID_SECURITY_GROUPID | 4
DATE_TIME | 5
SHA1_CHECKSUM | 6
REDACTION_DS1 | 7
REDACTION_DS2 | 8
REDACTION_DS3 | 9
FILESIZE | 10
EXTRACTED_TEXT_SHA1_CHECKSUM | 11
IS_ACTIVE | 11
EXTRACTED_TEXT_DS1 | 12
EXTRACTED_TEXT_SHA1_CHECKSUM | 12
EXTRACTED_TEXT_DS1 | 13
EXTRACTED_TEXT_DS2 | 13
EXTRACTED_TEXT_DS2 | 14
EXTRACTED_TEXT_DS3 | 14
EXTRACTED_TEXT_DS3 | 15
EXTRACTED_TEXT_FILESIZE | 15
EXTRACTED_TEXT_FILESIZE | 16
IS_ACTIVE | 16
IS_PROTECTED | 17
LOG_VERSION$$ | 18

24 rows selected.