Expressions passed to this function must have the following data types:
- date_timestamp_value = DATE, TIMESTAMP, or TIMESTAMP WITH TIME ZONE
- num_months = INTEGER
For the num_months argument, you can also pass values with data types that can be converted to INTEGER using the implicit data type conversion rules that apply to UDFs. Implicit type conversion is not supported for the date_timestamp_value argument.
For details, see “Compatible Types” in Teradata Vantage™ - SQL External Routine Programming , B035-1147 .
Since TIMESTAMP values are stored in UTC time within the database and lack a time zone, the session time zone is used to interpret the time stamp value within the function. For TIMESTAMP WITH TIME ZONE values, the time zone component is used to interpret the time stamp value within the function.
If the day component of date_timestamp_value is the last day of the month, or if the resulting month has fewer days than the day component of date_timestamp_value, OADD_MONTHS returns the last day of the resulting month. Otherwise, OADD_MONTHS returns a value that has the same day component as date_timestamp_value.
The difference between OADD_MONTHS and ADD_MONTHS is that if a month is added to an end-of-month date in OADD_MONTHS, the function always returns an end-of-month date. The following queries illustrate the difference between ADD_MONTHS and OADD_MONTHS:
- This query:
SELECT ADD_MONTHS ('2008-02-29', 1);
- This query:
SELECT OADD_MONTHS ('2008-02-29', 1);