MySQL 如何处理包含空值的表导出到CSV文件中
如果我们从包含NULL值的表中导出数据,MySQL会在CSV文件中为具有NULL值的记录中存储\N。可以用以下示例说明:
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示例
假设我们想要导出’tudent_info’表的值,包含以下数据 –
mysql> Select * from Student_info;
+------+---------+------------+------------+
| id | Name | Address | Subject |
+------+---------+------------+------------+
| 101 | YashPal | Amritsar | History |
| 105 | Gaurav | Chandigarh | Literature |
| 125 | Raman | Shimla | Computers |
| 130 | Ram | Jhansi | Computers |
| 132 | Shyam | Chandigarh | Economics |
| 133 | Mohan | Delhi | Computers |
| 150 | Saurabh | NULL | Literature |
+------+---------+------------+------------+
7 rows in set (0.00 sec)
我们可以看到结果在地址字段中有一个NULL值,其中id为150。现在以下查询将导出此表中的数据到Student_27.CSV中 –
mysql> Select * from Student_info INTO OUTFILE 'C:/mysql/bin/mysql-files/student_27.csv' FIELDS TERMINATED BY ',';
Query OK, 7 rows affected (0.02 sec)
上述查询已在Student_27.CSV文件中存储以下值 –
101 YashPal Amritsar History
105 Gaurav Chandigarh Literature
125 Raman Shimla Computers
130 Ram Jhansi Computers
132 Shyam Chandigarh Economics
133 Mohan Delhi Computers
150 Saurabh \N Literature
我们可以看到,MySQL在具有NULL值的表处存储\N。