how do i fix invalid number

Question

I am getting the error ORA-01722: invalid number when I run this code and I don't seem to know where the error is from:

ORA-01722: invalid number

INSERT INTO P2720515_TP
  SELECT PRO_ID,
         THEATRE_ID,
         CLIENT_ID,
         TIME_ID,
         PURCHASE#,
         PAYMENTMETHOD,
         DELIVERYMETHOD,
         T_SUM
    FROM (SELECT P.PRO_ID,
                 T.THEATRE_ID,
                 C.CLIENT_ID,
                 TM.TIME_ID,
                 PURCHASE#,
                 PAYMENTMETHOD,
                 DELIVERYMETHOD,
                 SUM(TOTALAMOUNT) T_SUM
            FROM OPS$YYANG00.PERFORMANCE    PER,
                 P2720515_TM                TM,
                 P2720515_P                 P,
                 P2720515_T                 T,
                 P2720515_C                 C,
                 OPS$YYANG00.TICKETPURCHASE TP
           WHERE PER.P# = P.PRO_NO
             AND PER.THEATRE# = T.THEATRE_NO
             AND TP.CLIENT# = C.C_NO
             AND EXTRACT(YEAR FROM PER.PDATE) = TM.YEAR
             AND EXTRACT(MONTH FROM PER.PDATE) = TM.MONTH
           GROUP BY P.PRO_ID,
                    T.THEATRE_ID,
                    C.CLIENT_ID,
                    TM.TIME_ID,
                    PURCHASE#,
                    PAYMENTMETHOD,
                    DELIVERYMETHOD);

Answer 1

when you trying to compare two different datatypes it usually gives that type of error (invalid number). or you are using aggregate function with no aggregate values.

check all values that comes in columns which you are trying to aggregate or in comparison.

you can also use cast function to make it solve quickly.