HOURSTART scalar function

Returns a TIMESTAMP at the start of AHOUR on the date AYEAR, AMONTH, ADAY, or at the start of the hour of ATIMESTAMP.

Prototypes

HOURSTART(AYEAR INTEGER, AMONTH INTEGER, ADAY INTEGER, AHOUR INTEGER)
HOURSTART(ATIMESTAMP TIMESTAMP)
HOURSTART(ATIMESTAMP VARCHAR(26))

RETURNS TIMESTAMP

Description

Returns a TIMESTAMP value representing the first microsecond of AHOUR in the date given by AYEAR, AMONTH, and ADAY, or of the timestamp given by ATIMESTAMP depending on the variant of the function that is called.

Parameters

AYEAR
If provided, the year component of the resulting timestamp.
AMONTH
If provided, the month component of the resulting timestamp.
ADAY
If provided, the day component of the resulting timestamp.
AHOUR
If provided, the hour component of the resulting timestamp.
ATIMESTAMP
If provided, the timestamp from which to derive the start of the hour. Either AYEAR, AMONTH, ADAY, and AHOUR, or ATIMESTAMP must be provided.

Examples

Truncate the specified timestamp to the nearest hour:

VALUES HOURSTART('2010-01-23 04:56:00');

1
--------------------------
2010-01-23-04.00.00.000000

Calculate the start of the first working day in 2011:

VALUES HOURSTART(2011, 1, DAY(
  CASE WHEN DAYOFWEEK(YEARSTART(2011)) IN (1, 7)
    THEN NEXT_DAYOFWEEK(YEARSTART(2011), 2)
    ELSE YEARSTART(2011)
  END), 9);

1
--------------------------
2011-01-03-09.00.00.000000

See Also