MySQL - DATA TYPES for time/date

Useful Functions - ALL the time & date functions may come in handy... some day

      MySQL - Date & Time Fcn's
                        -and-
      MySQL - Temporal Intervals

Dr. Dale's....set of go to functions is FAR more LIMITED

          now()
          current_date
          interval.... (ie, interval 1 day)

          timestampdiff  ( unit, leftOperand,  rightOperand )
          ie, timestampdiff( day , DOB,  NOW() )

A Few Examples....

#-------------------------------------------------------------
#   diff ... aka ... difference as in
#
#       THE DIFFERENCE BETWEEN TWO DATES,
#          for example
#                  date of birth -AND- this minute
#   Should this be measured in.... days? months? years? what?
#-------------------------------------------------------------

#--                      units  now-dob = Age, (-:
select *, TIMESTAMPDIFF(   DAY, DOB, NOW() ) as 'Age (days)'
        , TIMESTAMPDIFF( MONTH, DOB, NOW() ) as 'Age (mos)'
        , TIMESTAMPDIFF(  YEAR, DOB, NOW() ) as 'Age (yrs)'
      from pet;

          select * from pet    WHERE    pet.DOB > now() - interval 6 year;

          # LIVING pets born in the last six years?
          select * from pet    WHERE    pet.DOB > now() - interval 6 year
                                    AND DOD is NULL;
### DON'T USE   =NULL  Why not? 
                       The result of any arithmetic comparison with NULL is also NULL, 
                       so....you cannot obtain any meaningful results from such comparisons.

### DON'T use  ==NULL  Why not? 
                       No such operator in MySQL; Bad Syntax