select b.name, 
    left(convert(datetime, dateadd(day, 1-day(b.date), b.date), 20) 
, 10)as dt1,

    left(convert(datetime, dateadd(month, 1, dateadd(day, 1-day(b.date),b.date)) - 1, 20), 10) 
as dt2
  from battles b
----------
Guadalcanal	Nov 1 194	Nov 30 194
North Atlantic	May 1 194	May 31 194
North Cape	Dec 1 194	Dec 31 194
Surigao Strait	Oct 1 194	Oct 31 194