Perform date, time, and timestamp arithmetic using the Open Query File (OPNQRYF) command

Date, time, and timestamp values can be incremented, decremented, and subtracted. These operations might involve decimal numbers called durations. These topics include a definition of durations and a specification of the rules for performing arithmetic operations on date, time, and timestamp values.

• Durations
  A duration is a number representing an interval of time. This topic introduces various types of durations.
• Rules for date, time, and timestamp arithmetic
  The only arithmetic operations that can be performed on date and time values are addition and subtraction. If a date or time value is the operand of addition, the other operand must be a duration. This topic describes rules for performing date, time and timestamp arithmetic.
• Subtract dates
  The result of subtracting one date (DATE2) from another (DATE1) is a date duration that specifies the number of years, months, and days between the two dates.
• Increment and decrement dates
  The result of adding a duration to a date, or of subtracting a duration from a date, is itself a date.
• Subtract times
  The result of subtracting one time (TIME2) from another (TIME1) is a time duration that specifies the number of hours, minutes, and seconds between the two times.
• Increment and decrement times
  The result of adding a duration to a time, or of subtracting a duration from a time, is itself a time. Any overflow or underflow of hours is discarded, thereby ensuring that the result is always a time.
• Subtract timestamps
  The result of subtracting one timestamp (TS2) from another (TS1) is a timestamp duration that specifies the number of years, months, days, hours, minutes, seconds, and microseconds between the two timestamps.
• Increment and decrement timestamps
  The result of adding a duration to a timestamp, or of subtracting a duration from a timestamp, is itself a timestamp.