The result of the INTERVAL (p) IQ function is the value of (END(p) - BEGIN(p)) IQ, where argument p is a Period expression and IQ is an interval qualifier.
If the argument is NULL, the result is NULL.
The result of the INTERVAL (p) IQ function is the value of (END(p) - BEGIN(p)) IQ, where argument p is a Period expression and IQ is an interval qualifier.
If the argument is NULL, the result is NULL.