O problema é como o MySQL interpreta um campo vazio vs um campo ausente . Dos documentos para LOAD DATA INFILE ...
Neste caso, parece que o MySQL o considera vazio . Você pode ver isso em
show warnings . mysql> show warnings;
+---------+------+------------------------------------------------------------+
| Level | Code | Message |
+---------+------+------------------------------------------------------------+
| Warning | 1265 | Data truncated for column 'customerReviewAverage' at row 2 |
| Warning | 1265 | Data truncated for column 'customerReviewAverage' at row 3 |
+---------+------+------------------------------------------------------------+
2 rows in set (0.00 sec)
Considerando que, se removermos as vírgulas à direita, o campo ficará ausente ...
19658847,Glanzlichter - CD,,12.99,5.0
19658856,Glanzlichter - CD,,6.99
19658865,Glanzlichter - CD,,8.99
1965886,Beach Boys '69 - CASSETTE,,6.99,4.5
Em seguida, os dados são definidos como nulos.
mysql> show warnings;
+---------+------+--------------------------------------------+
| Level | Code | Message |
+---------+------+--------------------------------------------+
| Warning | 1261 | Row 2 doesn't contain data for all columns |
| Warning | 1261 | Row 3 doesn't contain data for all columns |
+---------+------+--------------------------------------------+
mysql> select * from products;
+----------+---------------------------+-------------+--------------+-----------------------+
| sku | name | description | regularPrice | customerReviewAverage |
+----------+---------------------------+-------------+--------------+-----------------------+
| 19658847 | Glanzlichter - CD | NULL | 12.99 | 5 |
| 19658856 | Glanzlichter - CD | NULL | 6.99 | NULL |
| 19658865 | Glanzlichter - CD | NULL | 8.99 | NULL |
| 1965886 | Beach Boys '69 - CASSETTE | NULL | 6.99 | 4.5 |
+----------+---------------------------+-------------+--------------+-----------------------+
4 rows in set (0.00 sec)
Fazendo a mesma coisa para
@customerReviewAverage como para @description funcionou para mim no MySQL 5.7. LOAD DATA
LOCAL INFILE 'product.csv'
INTO TABLE Products
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n'
(sku, name, @description, regularPrice, @customerReviewAverage)
SET description = IF(@description='',NULL,@description),
customerReviewAverage = IF(@customerReviewAverage='',NULL,@customerReviewAverage);
mysql> select * from products;
+----------+---------------------------+-------------+--------------+-----------------------+
| sku | name | description | regularPrice | customerReviewAverage |
+----------+---------------------------+-------------+--------------+-----------------------+
| 19658847 | Glanzlichter - CD | NULL | 12.99 | 5 |
| 19658856 | Glanzlichter - CD | NULL | 6.99 | NULL |
| 19658865 | Glanzlichter - CD | NULL | 8.99 | NULL |
| 1965886 | Beach Boys '69 - CASSETTE | NULL | 6.99 | 4.5 |
+----------+---------------------------+-------------+--------------+-----------------------+
4 rows in set (0.00 sec)
