如何将sql中的数字转换为日期

Question

I am fetching data from oracle using sql in python. There are columns having integer values. I want to convert those column values to dates while retrieving data.

connection = cx_Oracle.connect(user, pwd, dsn, encoding="UTF-8")
cursor = connection.cursor()
results = cursor.execute("SELECT TO_DATE(DATECREATED,'yyyymmdd') as DATECREATED from ARADMIN.EPM_TechnicianInformation").fetchall()

It's not working.

Answer 1

the above query is giving me errors - DatabaseError:

 ORA-01843: not a valid month

From Oracle 12, you can add a clause to handle errors during conversion due to invalid data:

SELECT TO_DATE(
         DATECREATED
         DEFAULT NULL ON CONVERSION ERROR,
         'yyyymmdd'
       ) as DATECREATED
FROM   ARADMIN.EPM_TechnicianInformation

Which for the sample data:

CREATE TABLE ARADMIN.EPM_TechnicianInformation ( datecreated ) AS
SELECT 20210929 FROM DUAL UNION ALL  -- A valid date
SELECT 20211301 FROM DUAL;           -- An invalid date as month = 13

Outputs:

DATECREATED
2021-09-29 00:00:00
<null>

db<>fiddle here