Sorry for my mistake. Should be: First expression returns 2009-03-01 23:59 but the second returns 2009-03-02 00:00

I think the tricky data are bad. Conversion from datetime string to smalldateime for some data give unexpected results: declare @t table(t smalldatetime)insert into @tselect cast('2009-03-01 23:59:29' as smalldatetime) union allselect cast('2009-03-01 23