MySQL LOAD DATA INFILE Error Code 1366. Incorrect integer value: ' '
To set NULL you just need your table to have allow nulls.

If you want to change it to some default value in case of nulls/missing values, you need to specify individual column names as below:

LOAD DATA INFILE "/home/mycsv.txt" 
INTO TABLE inbound.master_data
FIELDS TERMINATED BY ','  
OPTIONALLY ENCLOSED BY '"' 
LINES TERMINATED BY '\r\n'
    (name,proddescr,country,thing,charA,datecol,charB,@VAL)
    set numberCol=if(@VAL is null, 0, @VAL);


You can change that 0 to any other default value.

This blog post has many other interesting load data scenarios you might want to learn. (go through the comments as well).