Sqlite SQL with datetime formatting

I have a scenario that generated datetime and I need to export it as SQL Inserts for sqlite DB.

my formula is
concat(‘strftime(’, __readingdate, “, %Y-%m-%d %H:%M:%S”)
concat(“strftime(’”, __readingdate, “’,’%Y-%m-%d %H:%M:%S’)”)

and my SQL shows as
insert into READINGS (num, value, readingdate) values (6, 31.78, ‘strftime(2019-05-10 23:45:00, %Y-%m-%d %H:%M:%S’);

rather than
insert into READINGS (num, value, readingdate) values (6, 31.78, strftime(‘2019-05-10 23:45:00’, ‘%Y-%m-%d %H:%M:%S’);

I have tried several variations of quoted options but this is the closest - but not a valid format.

Would appreciate some insight as to what I’m doing wrong.

Thanks