django annotate datetime field to char

To annotate a Django DateTimeField as a CharField, you can use the ExpressionWrapper and Func classes from django.db.models. Here are the steps:

  1. Import Required Modules:python from django.db.models import ExpressionWrapper, Func, CharField from django.utils import timezone

  2. Create Annotated QuerySet:python annotated_queryset = YourModel.objects.annotate( char_datetime=ExpressionWrapper( Func( timezone.Trunc('your_datetime_field', 'minute'), function='TO_CHAR', template="YYYY-MM-DD HH:MI AM" ), output_field=CharField() ) )

Replace 'your_datetime_field' with the name of your DateTimeField in the YourModel model.

  1. Explanation:
  2. annotate() is used to add the annotated field to the queryset.
  3. ExpressionWrapper allows adding an expression to the queryset.
  4. Func creates a database function expression using the TO_CHAR function to convert the DateTimeField to a character string formatted as desired (YYYY-MM-DD HH:MI AM in this case).
  5. timezone.Trunc() truncates the datetime field to the specified minute precision.

  6. output_field=CharField() specifies the output field as a CharField.

  7. Access the Annotated Field: After executing the query, you can access the annotated field char_datetime in the queryset results.

Remember to replace 'your_datetime_field' with the actual name of the DateTimeField in your Django model.