[Environment]
- AWS Aurora or Mysql
[Problem]
- When csv file is imported to string column,If the criteria are enclosed in single quotes, will not produce the desired result.
where target_column = '31000000000';
- If the criteria are not enclosed in single quotes,ok.
where target_column = 31000000000;
[Cause]
- If you import a csv file without double quotes in the loader,Imports up to unnecessary line feed codes.
- Line feed code is usually invisible in database.It is necessary to look in hexadecimal.
| value | memo | hex(value) |
|---|---|---|
| 31000000000 | csv | 33313030303030303030300D |
| 31000000000 | DML | 3331303030303030303030 |
ā0Dā is Line feed code of UTF-8.
[point]rule of mysql.
For conditional expression [string = number],Compare strings on left side as decimal numbers.line feed code is invalid.
For conditional expression [string = string],The character strings on the left side are compared as they are.line feed code is valid.
[How to]
- To see the line feed code, convert it to hexadecimal.my case is LF.In hexadecimal, it is ā0dā.
- This DML deletes only the line feed code.
update target_table_name set target_column_name = TRIM( UNHEX('0D') FROM target_column_name );
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