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Interval Arithmetic
Intervals can be added to and subtracted from other intervals in most cases. The following table shows the possible combinations of addition and subtraction between two intervals, and the resulting interval types ("*" means that an arithmetic operation is not permitted between the two interval types):
+ | – DAYS MONTHS YEARS HOURS MINUTES SECONDS MICROSECONDS DAYS DAYS * * SECONDS SECONDS SECONDS SECONDS MONTHS * MONTHS MONTHS * * * * YEARS * MONTHS MONTHS * * * * HOURS SECONDS * * SECONDS SECONDS SECONDS SECONDS MINUTES SECONDS * * SECONDS SECONDS SECONDS SECONDS SECONDS SECONDS * * SECONDS SECONDS SECONDS SECONDS MICROSECONDS SECONDS * * SECONDS SECONDS SECONDS SECONDS
Intervals can also be involved in addition, subtraction, multiplication, and division operations with numeric expressions as operands. The interval can appear on either side of an operator (+, , *, /) in all cases except one: a numeric expression cannot be divided by an interval. For example, "12/(3 days)" is an invalid arithmetic operation.The following table lists the interval type resulting from the arithmetic interaction of a numeric expression and an interval of a given type (the result is the same for each operator):
Interval Result Type DAYS DAYS MONTHS MONTHS YEARS MONTHS HOURS SECONDS MINUTES SECONDS SECONDS SECONDS MICROSECONDS SECONDS
Examples
Expression Result1 DAY + 1 HOUR 90000.000000 (seconds)60 SECONDS + 500 MICROSECONDS 60.000500 (seconds)12 MONTHS + 1 YEAR 24 (months)1 YEAR * 2 24 (months)28 DAYS / 7 4 (days)8 * 2 HOURS 57600 (seconds)20 MICROSECONDS + 2 2.000020 (seconds)1 DAY - (30 + 30 MINUTES) 84570.000000 (seconds)
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Intervals and Date/Time Values |
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