INTERVAL qual1 TO qual2

Syntax 1: year-month class interval

 INTERVAL YEAR[(precision)] TO MONTH
|INTERVAL YEAR[(precision)] TO YEAR
|INTERVAL MONTH[(precision)] TO MONTH

Syntax 2: day-time class interval

 INTERVAL DAY[(precision)] TO FRACTION[(scale)]
|INTERVAL DAY[(precision)] TO SECOND
|INTERVAL DAY[(precision)] TO MINUTE
|INTERVAL DAY[(precision)] TO HOUR
|INTERVAL DAY[(precision)] TO DAY

|INTERVAL HOUR[(precision)] TO FRACTION[(scale)]
|INTERVAL HOUR[(precision)] TO SECOND
|INTERVAL HOUR[(precision)] TO MINUTE
|INTERVAL HOUR[(precision)] TO HOUR

|INTERVAL MINUTE[(precision)] TO FRACTION[(scale)]
|INTERVAL MINUTE[(precision)] TO SECOND
|INTERVAL MINUTE[(precision)] TO MINUTE

|INTERVAL SECOND[(precision)] TO FRACTION[(scale)]
|INTERVAL SECOND[(precision)] TO SECOND

|INTERVAL FRACTION TO FRACTION[(scale)]

1. precision defines the number of significant digits of the first qualifier, it must be an integer from 1 to 9. For YEAR, the default is 4. For all other time units, the default is 2. For example, YEAR(5) indicates that the INTERVAL can store a number of years with up to 5 digits.
2. scale defines the scale of the fractional part, it can be 1, 2, 3, 4 or 5.

Usage

The INTERVAL data type stores a span of time, the difference between two points in time. It can also be used to store quantities that are measured in units of time, such as ages or times.

The INTERVAL data type falls in two classes, which are mutually exclusive:

• Year-time intervals store a span of years, months or both.
• Day-time intervals store a span of days, hours, minutes, seconds and fraction of seconds, or a contiguous subset of those units.

INTERVAL variables can be assigned from string literals by using the format YYYY-MM-DD hh:mm:ss.fffff.

INTERVAL values can be negative.

INTERVAL arithmetic involves DATETIME as well as DECIMAL operands:

MAIN
  DEFINE i1 INTERVAL YEAR TO MONTH
  DEFINE i2 INTERVAL DAY(5) TO MINUTE
  LET i1 = "2342-4"
  LET i2 = "23423 12:34"
  DISPLAY i1, i2
END MAIN