'Empty column does not return NULL or empty

I imported a CSV file using LOAD DATA INFILE and have this column called Context.

The entire column appears empty - which it shouldn't be, because I already set the DEFAULT to be NULL. So I expected NULL to appear in the entire column.

I have tried if it is empty or NULL but the code below returns 0

SELECT COUNT(*) FROM table 
WHERE Context IS NULL OR Context = '';

So now I do not know where the problem is.

FYI: This column is in TEXT datatype and I could change it to VARCHAR, but NOT INT - I don't know if it's related to the problem.

mysqlsql


Solution 1:[1]

Based on this thread, I modified my query to the following and was able to solve the problem.

UPDATE table SET Context = NULLIF(Context,' ');
UPDATE table SET Context = NULLIF(Context, '\t');
UPDATE table SET Context = NULLIF(Context, '\n');
UPDATE table SET Context = NULLIF(Context, '\r');

So the original problem could be caused by either \t , \n or \r.

Sources

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Source: Stack Overflow

Solution Source
Solution 1 Truc Tran

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