To_char function help

Question

Hi All,
I have run this query in my oracle database
SELECT
J.NAME,
(CASE J.STATUS WHEN 'Completed' THEN COUNT(J.STATUS) ELSE 0 END) CURRENT_MONTH_COMPLETE,
(CASE J.STATUS WHEN 'Pending for Process Engine' THEN COUNT(J.STATUS) ELSE 0 END) CURRENT_MONTH_IN_PROGRESS
FROM
CMN_SCH_JOBS_V J
WHERE
J.STATUS IN ('Completed','Pending for Process Engine') AND J.LANGUAGE_CODE='en'
and to_char(J.START_DATE,MM')=12
GROUP BY J.NAME,J.STATUS;I have a doubt regarding this
to_char(J.START_DATE,MM')=12Basically to_char() function returns a string value, but when it is equated against a numeric value oracle should raise an error right, this query is running fine. Please tell why this is happening.
Regards
Praveen Vuppalapati

Answer 1

What a strange query. I'd expect it to be either:
SELECT
J.NAME,
J.STATUS
COUNT(*)
FROM
CMN_SCH_JOBS_V J
WHERE
J.STATUS IN ('Completed','Pending for Process Engine') AND J.LANGUAGE_CODE='en'
and to_char(J.START_DATE,MM')=12
GROUP BY J.NAME,J.STATUS;... or ...
SELECT
J.NAME,
SUM(CASE J.STATUS WHEN 'Completed' THEN 1 ELSE 0 END) CURRENT_MONTH_COMPLETE,
SUM(CASE J.STATUS WHEN 'Pending for Process Engine' THEN 1 ELSE 0 END) CURRENT_MONTH_IN_PROGRESS
FROM
CMN_SCH_JOBS_V J
WHERE
J.STATUS IN ('Completed','Pending for Process Engine') AND J.LANGUAGE_CODE='en'
and to_char(J.START_DATE,'MM')=12
GROUP BY J.NAME;Ought to wrap the to_char() in a to_number as well, really.