For date and time stamp queries if the value is null then what is returned for low-date and low-timestamp
(0000-00-00 and 0000-00-00-00.00.00.000000)
(0001-01-01 and 0001-01-01-01.01.01.000001)
(0001-01-01 and 0001-01-01-00.00.00.000000)
(0001-01-01 and 0000-00-00-00.00.00.000000)