Date conversion function
Add_MONTHS (D, N)
N is the multiple of the month: for example D = 20041116 add_months (to_date (d, 'YYYYMMDD', 1) result is 20041216
2. Digital conversion function
TO_NUMBER (C, '999, 999')
Conversion string is Number type
For example: c = '158,000' TO_NUMBER (C, '999, 999') = 158000
