Vertica copy query and Null Value - vertica

Question

I have a table in vertica Database, its column CON_BRWR is Varchar(100) Not Null.
I am applying encryption on this column. If this column gets empty string, that row should be rejected but due to encryption it encrypts the empty string and Null also.
To overcome this problem i tried this solution
COPY myschema.CON_BIZ ( __tempCON_BRWR FILLER VARCHAR(100),
CON_BRWR as Case WHEN __tempCON_BRWR = '' THEN NULL ELSE AESEncrypt(__tempCON_BRWR,'abcdefg') end
) FROM STDIN ENCLOSED BY '"' delimiter ',' ENFORCELENGTH SKIP 1 rejected data as table ErrorTable no commit;
that if __tempCON_BRWR filler gets empty string it should not encrypt value but in any case
it is going in else condition
I am stuck, any kind of help will be appreciated!

Answer 1

it is going in else condition
Your syntax a little problematic for Vertica parser, see example for right syntax.
NOTE:
But it will not solve your main problem -> reject row.
DDL:
CREATE TABLE public.haroon
(
id int,
raw varchar(100),
encrypted varchar(100)
);
Populate table with COPY FROM STDIN statement:
(most important part, take a look on CASE syntax and on definition of NULL in copy)
copy haroon(
id,
rawdata filler varchar(100),
raw as rawdata,
encrypted as case rawdata = '' or rawdata is NULL
when TRUE then NULL
else AESEncrypt(rawdata, 'secret')
end)
from stdin ENCLOSED BY '"' NULL as '' delimiter ',' direct abort on error;
daniel=> \e
Enter data to be copied followed by a newline.
End with a backslash and a period on a line by itself.
>> 1,""
>> 2,
>> 3,foo
>> \.
{column} as case {filler} = '' or {filler} is NULL when TRUE then NULL else AESEncrypt({filler}, {password})
COPY ... NULL AS ''
Test:
daniel=> select id, raw, encrypted::varchar(3), encrypted is NULL from haroon ;
id | raw | encrypted | ?column?
----+-----+-----------+----------
1 | | | t
2 | | | t
3 | foo | �� | f
(3 rows)
You can see that 2 first rows (id = [1,2]) contains NULL in encrypted column, data loaded without any issues.