The best replacement for datetime is timestamp.

The best alternatives to datetime are rated as following:
★★★★★  timestamp
★★★★  datetime2
★★★★  smalldatetime
★★★  date
★★  datetimeoffset
★★  time
★  timestamp rails
★  datetime
★  time python
★  time ruby
★  localdatetime
★  datetime-local
★  date sql
★  date java
  nullable datetime
  int mysql
  timestamp sql server
  date sql server
  oracle timestamp
  smalldatetime sql server
  timestamp mysql

Your alternative for datetime is not listed? Suggest!
Speaking about datetime, one probably shouldn't forget about timezone.

Other search terms related to datetime and their ratings are:
★★★★★ timezone
★★ milliseconds in sql server
You have in mind a companion for datetime and it is not yet here? Propose!



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datetime
timestamp
datetime2