What is the difference between NULL and \N while loading data from a csv using load data local infile

I have a table which has four fields

create table test_hc1(cola int,colb int,colc varchar(20),cold int);

Now, I am trying to load following data

1,2,\N,4

and the third field in table is coming out as NULL, which is the expected result.

In another case, I am trying to load following data

1,2,NULL,4

and it is also loading the third field as NULL.

Here is my question : What is the difference between using the two(\N, NULL) ?

I am using

LOAD DATA LOCAL INFILE 'PATH_TO_DATAFILE'
INTO TABLE TABLE_NAME FIELDS TERMINATED BY x'01';

Any help is appreciated.

Thanks

Depends on your options FIELDS and LINES used in the LOAD DATA statement.

MySQL documentation

From MySQL doc:


Handling of NULL values varies according to the FIELDS and LINES
options in use:


For the default FIELDS and LINES values, NULL is written as a field
value of \N for output, and a field value of \N is read as NULL for
input (assuming that the ESCAPED BY character is “\”).


If FIELDS ENCLOSED BY is not empty, a field containing the literal
word NULL as its value is read as a NULL value. This differs from the
word NULL enclosed within FIELDS ENCLOSED BY characters, which is read
as the string 'NULL'.


If FIELDS ESCAPED BY is empty, NULL is written as the word NULL.


With fixed-row format (which is used when FIELDS TERMINATED BY and
FIELDS ENCLOSED BY are both empty), NULL is written as an empty
string. Note that this causes both NULL values and empty strings in
the table to be indistinguishable when written to the file because
both are written as empty strings. If you need to be able to tell the
two apart when reading the file back in, you should not use fixed-row
format.

StackExchange Database Administrators Q#46670, answer score: 3