Strange behaviour of Regexp_replace in a Hive SQL query

Question

I have some input information where I\'m trying to remove the part .0 from my input where an ID string ends with .0.

select student_i

Answer 1

Dot in regexp has special meaning (it means any character). If you need dot (.) literally, it should be shielded using double-slash (in Hive). Also add end-of-the-line anchor($):

with mydata as (
select stack(3,
'01-0230984.03',
'12345098.0',
'34567.0'
) as str
)

select regexp_replace(str,'\\.0$','') from mydata;

Result:

01-0230984.03
12345098
34567

Regexp '\\.0$' means dot zero (.0) literally, end of the line ($).