创建要与一起使用的示例数据库和表。

create database `test`;
use `test`;
create table `test` (`value` float(10,2) null);
insert into test (value) values (null);
select value  from test;
+-------+
| value |
+-------+
|  NULL |
+-------+
1 row in set (0.00 sec)

现在我想创建一个txt文件，当您加载它时，可以将空数据加载到测试表中。

delete from test;

这是我的数据文件名为 test.txt 在vim中显示（：set list）。

将文件加载到表中。

LOAD DATA LOCAL INFILE  "test.txt"
INTO TABLE test
FIELDS TERMINATED BY '\t'
LINES TERMINATED BY '\n' \w;
select value from test;
+-------+
| value |
+-------+
|  0.00 |
|  0.00 |
|  0.00 |
|  0.00 |
|  0.00 |
+-------+

如何加载 null 的数据 value 我的案子里有文件吗？
如何创建这种数据文件，值字段是 null 你装完之后？
运行时environment:win10+mysql-5.7.

select version();
+-----------+
| version() |
+-----------+
| 5.7.22    |
+-----------+
1 row in set (0.03 sec)

在vim中显示test.txt文件 set list .

\N$
\N^I$

case:without set
加载它而不加载 (value) SET value = (CASE WHEN @value IS NULL THEN NULL ELSE @value END) .

LOAD DATA LOCAL INFILE  "f:/test.txt"
INTO TABLE test
FIELDS TERMINATED BY '\t'
LINES TERMINATED BY '\n' \W;

输出：

Warning (Code 1265): Data truncated for column 'value' at row 1
Warning (Code 1262): Row 2 was truncated; it contained more data than there were input columns

select * from  test;
+-------+
| value |
+-------+
|  0.00 |
|  NULL |
+-------+

case:with set
把它装上 (value) SET value = (CASE WHEN @value IS NULL THEN NULL ELSE @value END) .

delete from test;
LOAD DATA LOCAL INFILE  "f:/test.txt"
INTO TABLE test
FIELDS TERMINATED BY '\t'
LINES TERMINATED BY '\n' 
(value)SET value = (CASE WHEN @value IS NULL THEN NULL ELSE @value END) \W;

输出：

Warning (Code 1265): Data truncated for column 'value' at row 1
Warning (Code 1262): Row 2 was truncated; it contained more data than there were input columns

 select * from test;
+-------+
| value |
+-------+
|  NULL |
|  NULL |
+-------+

谢谢@schwern。

LOAD DATA LOCAL INFILE  "f:/test.txt"
INTO TABLE test
FIELDS TERMINATED BY '\t'
LINES TERMINATED BY '\r\n'  \W;

两者都可以正常工作，没有任何警告。