T-SQL Query Returning Items It Shouldn't Be

Question

Here\'s the scenario. The column in question is called \'datein\' and it\'s type is \'datetime\'. I have three rows with the value of \'2009-10-01 00:00:00.000\' for \'datein\

Answer 1

The DATETIME accuracy is 0.00333 seconds. So you need to go to '2009-09-30 23:59:59.998' so it doesn't round up to Oct 1st.

For example:

select '2009-09-30 23:59:59.994', 
  cast('2009-09-30 23:59:59.994' as datetime)
union all select '2009-09-30 23:59:59.995', 
  cast('2009-09-30 23:59:59.995' as datetime)
union all select '2009-09-30 23:59:59.996', 
  cast('2009-09-30 23:59:59.996' as datetime)
union all select '2009-09-30 23:59:59.997', 
  cast('2009-09-30 23:59:59.997' as datetime)
union all select '2009-09-30 23:59:59.998', 
  cast('2009-09-30 23:59:59.998' as datetime)
union all select '2009-09-30 23:59:59.999', 
  cast('2009-09-30 23:59:59.999' as datetime)

returns:

2009-09-30 23:59:59.994 2009-09-30 23:59:59.993
2009-09-30 23:59:59.995 2009-09-30 23:59:59.997
2009-09-30 23:59:59.996 2009-09-30 23:59:59.997
2009-09-30 23:59:59.997 2009-09-30 23:59:59.997
2009-09-30 23:59:59.998 2009-09-30 23:59:59.997
2009-09-30 23:59:59.999 2009-10-01 00:00:00.000