SQL: Combine columns to specific datetime and cast to UTC - sql

Question

I am using Oracle SQL. I want to convert three columns to datetime in sql.
My data looks like:
DAY (DATE) HOUR (NUMBER) HALFHOUR (NUMBER)
21.04.22 11 22
21.04.22 11 23
21.04.22 12 24
21.04.22 12 25
21.04.22 13 26
21.04.22 13 27
....
I need to combine each row to the following specific format, in one column:
2022-04-21T13:30:00.00Z
Moreover, it should be converted from an utc time where data comes from (like UTC+3) to UTC+0 automatically.
How do I do this? I googled a lot, but cant do it.
Thanks :)

Answer 1

The solution to your problem is:
SELECT T1.*,
TO_CHAR(FROM_TZ(TO_TIMESTAMP(DAY||' '||HOUR||':'||HALFHOUR, 'DD.MM.RR HH24:MI'), 'Europe/Berlin') AT TIME ZONE 'UTC', 'YYYY-MM-DD"T"HH24:MI:SS.ff2"Z"') as time_utc
FROM T1;
TO_TIMESTAMP:
TO_TIMESTAMP converts char of CHAR, VARCHAR2, NCHAR, or NVARCHAR2
datatype to a value of TIMESTAMP datatype.
Syntax is:
TO_TIMESTAMP( string1 [, format_mask] ['nlsparam'] )
FROM_TZ:
In Oracle Database, the FROM_TZ() function converts a timestamp value
and a time zone to a TIMESTAMP WITH TIME ZONE value. Pass the
timestamp value and the time zone as two separate arguments, and the
function returns them as a TIMESTAMP WITH TIME ZONE value.
Syntax is :
FROM_TZ(timestamp_value, time_zone_value)
time_zone_value all possible values an be found out using the below query:
SELECT * FROM V$TIMEZONE_NAMES;
The output generated using above two functions is the time in the germany time-zone and is converted to UTC time zone using the " AT TIME ZONE 'UTC' "
Then using TO_CHAR it is converted to the required format.
You can see the working sample example at the below link:
https://dbfiddle.uk/?rdbms=oracle_11.2&fiddle=b030170a2c5536b4f80f1287bbfe4aca