Date-truncation functions

Date-truncation functions return the start of the period that contains a date.

startofday

startofday(Date.Day)

Returns the start of the day.

startofweek(Date.Week)

Returns the Monday at the start of the week.

startofmonth(Date.Month)

Returns the first day of the month.

startofquarter(Date.Month)

Returns the first day of the calendar quarter.

startofhalf(Date.Month)

Returns January 1 or July 1 for the half-year containing the date.

startofyear(Date.Month)

Returns January 1 of the year. These functions are useful when source dates must be aligned with a model period.