Creating hash value from multiple columns - sql

Question

I have an example product sales table which consists of around 15 columns and a couple thousand rows. The columns I'm most interested in look like this:
product_type currency amount order_time delivered_time
hoodie GBP 60.0 2021-03-10 14:32:07 2021-03-13 16:05:52
shirt EUR 30.0 2021-03-20 19:22:32 2021-03-24 11:18:46
...
There currently is a unique identifier but it isn't useful for broad analysis, there can be multiple products in an order but they'd all have a different identifier so you can't match them up.
What i want to do is create a new identifier column using a hash function, I've used the below code and showed an example output of what I get:
SELECT *, Md5(product_type||currency||amount)
FROM sales
product_type currency amount identifier
Coat GBP 100.0 825be52c31f1d92584720466d743e2cf
Coat GBP 100.0 825be52c31f1d92584720466d743e2cf
This code works for the 3 columns that I've included in the hash function, but I also want to include the two DATETIME columns into the function but it doesn't work. I've used this code to try include them, the code runs but the hash values i get are completed different to each other even if all the values in the columns match up:
SELECT *, Md5(product_type||currency||amount||TRUNC(order_time)||TRUNC(delivered_time))
I've used the TRUNC function on the two date columns as I'm not too concerned about the exact minutes or seconds, mainly interested in just the date itself. How could I include the two datetime columns without it messing up the hash function?

Answer 1

Use to_char(date, 'YYYY-MM-DD') instead of TRUNC()
Md5(product_type||currency||amount||to_char(order_time,'YYYY-MM-DD')||to_char(delivered_time,'YYYY-MM-DD'))
Or if the datatype is string/varchar, use SUBSTRING(date,1,10)
Md5(product_type||currency||amount||SUBSTRING(order_time,1,10)||SUBSTRING(delivered_time,1,10))