Inserting Hive table content with special characters -Tab space and New Line - hive

Question

I am trying to select data with special characters specifically Tab and NewLine, from Hive tables filtering on the where clause. I have tried
I have tried like '%\\n%', like '%\\t%', like '%hex(9)%' etc but they dont seem to work.
Also tried to create a dummy table to insert such data and that does not work too. Please help out.

Answer 1

Use rlike '\\t' for tabs and rlike '\\n' for newlines (use double backslash):
hive> select 'a\tb' rlike '\\t'; --tabs
OK
true
Time taken: 0.075 seconds, Fetched: 1 row(s)
And for newlines:
hive> select 'a\nb' rlike '\\n'; --newline
OK
true
Time taken: 0.454 seconds, Fetched: 1 row(s)
Example of inserting values with newline and tab:
create table test_special_chars as
select 'a\nb' as a union all select 'a\tb';
Newlines are tricky. The thing is that table is text file by default and newline character is interpreted normally as new line, this is why when being selected, it returns one extra row:
select * from test_special_chars;
OK
a
b
a b
Actualy, insert of \n created extra line in the text file. This is what happened.
But if you create ORC table:
create table test_special_chars stored as ORC as select 'a\nb' as a union all select 'a\tb';
It works fine, because ORC is not text format and can store newlines:
select count(*) from test_special_chars where a rlike '\\n';
Returns:
OK
1
Time taken: 40.564 seconds, Fetched: 1 row(s)
When you select a from test_special_chars where a rlike '\\n', on the screen it will be also displayed as two lines, it is interpreted on select, but the difference between ORC and text file is that in ORC newline can be stored in value without creating additional row in the file. This is why rlike '\\n' works with ORC and does not work with textfile (not returning any rows), after inserting in textfile \n creates two separate lines in the file, in the ORC it does not.
And this is how to replace newlines with something else:
select regexp_replace(a,'\\n',' newline ') from test_special_chars where a rlike '\\n';
Result:
OK
a newline b
Time taken: 1.502 seconds, Fetched: 1 row(s)