Seeing ORA-01858: a non-numeric character was found where a numeric was expected

Question

The following is my query for Oracle SQL Developer:

INSERT INTO ENROLLMENTS (DATE,PARTNER_NAME,ENROLLMENTS)
    SELECT TO_CHAR(TS, 'DD-MON-YYYY HH AM') AS DATE, mrch_bnft_cd, COUNT(*)
    FROM ENROLLMENTS 
    WHERE TS > trunc(sysdate-1/24, 'HH') + 5/24 
    AND TS < trunc(sysdate, 'HH') + 5/24
    GROUP BY TO_CHAR(TS, 'DD-MON-YYYY HH AM'), mrch
    ORDER BY TO_CHAR(TS, 'DD-MON-YYYY HH AM'), mrch_bnft

I get an error

ORA-01858: a non-numeric character was found where a numeric was expected error

but the error is not telling me where. Any ideas?

DATE = TIMESTAMP(6)
TS = TIMESTAMP(6)  
PARTNER = VARCHAR2(35 BYTE)  
ENROLLMENTS = NUMBER  
MRCH_BNFT= VARCHAR2(35 BYTE)

Answer 1

Basically you are trying to store a string which represents a date in a timestamp field. If you replace:

TO_CHAR(TS, 'DD-MON-YYYY HH AM')

by

TRUNC(TS, 'hh24')

at all 4 places it should work.

INSERT INTO ENROLLMENTS (DATE,PARTNER_NAME,ENROLLMENTS)
    SELECT   TRUNC(TS, 'hh24') AS DATE, mrch_bnft_cd, COUNT(*)
    FROM     ENROLLMENTS 
    WHERE    TS > trunc(sysdate-1/24, 'HH') + 5/24 
    AND      TS < trunc(sysdate, 'HH') + 5/24
    GROUP BY TRUNC(TS, 'hh24'), mrch
    ORDER BY TRUNC(TS, 'hh24'), mrch_bnft