The day-time interval has to do with the difference between times and contains a day value, an hour value, a minute value, a second value, or some combinations of these.

Some sample formats are:

INTERVAL DAY
INTERVAL DAY(precision)
INTERVAL HOUR
INTERVAL HOUR(precision)
INTERVAL MINUTE
INTERVAL MINUTE(precision)
INTERVAL SECOND
INTERVAL SECOND(fractional_precision)
INTERVAL DAY TO HOUR
INTERVAL DAY(precision) TO HOUR
INTERVAL DAY TO MINUTE
INTERVAL DAY(precision) TO MINUTE
INTERVAL DAY TO SECOND
INTERVAL DAY(precision) TO SECOND
INTERVAL DAY(precision) TO SECOND(fractional_precision)
INTERVAL HOUR TO SECOND
...
INTERVAL HOUR(precision) TO SECOND
...
INTERVAL MINUTE(precision) TO SECOND(fractional_precision)
...
etc.