How to convert a string to timestamp with milliseconds in Hive

I found a way to avoid the messy concatenation of substrings using the following code:

select cast(regexp_replace('20141014123456789', 
                           '(\\d{4})(\\d{2})(\\d{2})(\\d{2})(\\d{2})(\\d{2})(\\d{3})',
                           '$1-$2-$3 $4:$5:$6.$7') as timestamp) 

i had the date field in this form 2015-07-22T09:00:32.956443Z(stored as string). i needed to do some date manipulations. the following command even though little messy worked fine for me:)

select cast(concat(concat(substr(date_created,1,10),' '),substr(date_created,12,15)) as timestamp) from tablename;

this looks confusing but it is quite easy if you break it down. extracting the date and time with milliseconds and concat a space in between and then concat the whole thing and casting it into timestamp. now this can be used for date or timestamp manipulations.

A simple strategy would be to use date_format(arg1, arg2), where arg1 is the timestamp either as formatted string, date, or timestamp and the arg2 is the format of the string (in arg1). Refer to the SimpleDateFormat java documentation for what is acceptable in the format argument.

So, in this case:

date_format('20141014123456789', 'yyyyMMddHHmmssSSS')

would yield the following string: '2014-10-14 12:34:56.789' which can then be cast as timestamp:

cast(date_format('20141014123456789', 'yyyyMMddHHmmssSSS') as timestamp)

The above statement would return timestamp (as desired).