calculate the quarter from a string value in hive - string

Question

I have a requirement to fetch the quarter from a string field using hive version less than <1.3 so cant use quarter feature
sample data format in string field say abc--20210415
I tried doing it by using
CONCAT('T',(INT((MONTH(from_unixtime(unix_timestamp(abc,'yyyymmdd')))-1)/3)+1))
but its showing T1 instead it should show T2 (since april comes in second quarter 20210415) but this expression does not convert string to date before calculating quarter
So, i converted it to date using casting
cast(to_date(from_unixtime(unix_timestamp(date, 'yyyymmdd'))) as date)
it converted but output was 2021-01-15 and the same was converted to quarter using
CONCAT('T',(INT((MONTH(cast(to_date(from_unixtime(unix_timestamp(qc_creation_date, 'yyyymmdd'))) as date))-1)/3)+1))
Is there a way around to resolve this issue where in for ex: string 20210415 should give the output as T2 .Kindly help
Regards

Answer 1

i got the solution
CONCAT('Q',(INT((MONTH(cast(to_date(from_unixtime(unix_timestamp(abc, 'yyyyMMdd'))) as date))-1)/3)+1))
Thanks

Answer 2

Your date format yyyyMMdd can be efficiently converted to Hive format yyyy-MM-dd using regexp_replace function instead of unix_timestamp+from_unixtime functions which are using SimpleDateFormat. Bug in your query is wrong format template, it should be 'yyyyMMdd', see SimpleDateFormat for reference. But regexp_replace is much simpler, use unix_timestamp+from_unixtime only if not possible to do the same using regexp_replace.
Do not need to cast it to Date, string works fine.
For Hive < 1.3.0 extract month and use ceil(month/3.0):
select ceil(month(regexp_replace('20210415','(\\d{4})(\\d{2})(\\d{2})','$1-$2-$3'))/3.0) -- returns 2
Even simpler method:
select ceil(regexp_extract('20210415','^(\\d{4})(\\d{2})',2)/3) --returns 2
And since Hive 1.3.0 there is quarter(date/timestamp/string) function.
Demo:
quarter(regexp_replace('20210415','(\\d{4})(\\d{2})(\\d{2})','$1-$2-$3')); --Returns 2