Get a substring in hive - hive

Question

I am trying to get a substring of a string from Hive. I have a string as this one: 2017-06-05 09:06:32.0
What I want is to get the first two digits from hour, that is, 09.
I get the entire hour with this command:
SELECT SUBSTR(hora,11) AS subhoras FROM axmugbcn18.bbdd WHERE hora = '2017-06-05 09:06:32.0'
The result of the command is: 09:06:32.0
In order to get only 09 I try this command:
SELECT REGEXP_EXTRACT(hora,'\d\d') AS subhoras FROM axmugbcn18.bbdd WHERE hora = '2017-06-05 09:09:32.0'
but results are blank.
How can I retrieve only the two digits of hour?
Thanks

Answer 1

There are several ways you can extract hours from timestamp value.
1.Using Substring function:
select substring(string("2017-06-05 09:06:32.0"),12,2);
+------+--+
| _c0 |
+------+--+
| 09 |
+------+--+
2.Using Regexp_Extract:
select regexp_Extract(string("2017-06-05 09:06:32.0"),"\\s(\\d\\d)",1);
+------+--+
| _c0 |
+------+--+
| 09 |
+------+--+
3.Using Hour:
select hour(timestamp("2017-06-05 09:06:32.0"));
+------+--+
| _c0 |
+------+--+
| 9 |
+------+--+
4.Using from_unixtime:
select from_unixtime(unix_timestamp('2017-06-05 09:06:32.0'),'HH');
+------+--+
| _c0 |
+------+--+
| 09 |
+------+--+
5.Using date_format:
select date_format(string('2017-06-05 09:06:32.0'),'hh');
+------+--+
| _c0 |
+------+--+
| 09 |
+------+--+
6.Using Split:
select split(split(string('2017-06-05 09:06:32.0'),' ')[1],':')[0];
+------+--+
| _c0 |
+------+--+
| 09 |
+------+--+

Answer 2

Try the below:
select
'2017-06-05 09:06:32.0' as t,
hour('2017-06-05 09:06:32.0'), -- output: 9
from_unixtime(unix_timestamp('2017-06-05 09:06:32.0'),'HH') -- output: 09
from table_name;
You can either try hour or unixtimestamp to get the desired result.
Hope this helps :)