The
dateadd function calculates a new date by adding a period to a starting date. The numeric expression
start_date must be in YYYYMMDD (year/month/day) format. If no year is present, then the current or previous year is assumed in order satisfy the condition that the date is not in the future (based on the computer's system clock). The numeric expression
period is the amount of time that is added to the starting date, and defaults to days. Alternatively, an optional string expression,
period_type, modifies the period, and can be one of the following values:
If the period is not an integer, the period will be modified and the calculation will use days. For example, the following calculations are identical: