load data infile optionally enclosed by not working as expected
If MySQL splits a quoted CSV value into separate columns, you can fix the import by checking the enclosure, delimiter, and escaping rules. Most cases take only a few minutes to isolate. The symptom behind load data infile optionally enclosed by not working as expected usually comes from one of three places: Incorrect quoting: The SQL generated by PHP doesn't contain the enclosure character you…
MySQL's `load data infile` statement with `optionally enclosed by` may not function correctly due to various reasons. The issue typically stems from three main sources: incorrect quoting, mismatched CSV formatting, or unexpected field structure.
The `optionally enclosed by` command signals the import parser to recognize double-quoted fields. Inside a properly enclosed value, a comma should remain part of that value and not act as a column separator. If this doesn't occur, inspect the SQL and CSV bytes, verify the escape rules, and test the import directly in MySQL.
A simple fix involves stopping MySQL from splitting commas inside quotes. For instance, given a CSV record with four fields:
`ABSOLUTE,Glenn,Anakie, Cool Synd, Super Cool`
There are four columns - company, first_name, city, and owner. A broken import could result in five values instead of four:
`ABSOLUTE Glenn Anakie Cool Synd Super Cool`
The double quotes should disappear, while the internal comma remains. The command used is based on documented MySQL syntax, but isn't specific to your database or CSV. One key aspect to note: `OPTIONALLY` does not alter how MySQL reads enclosure characters during an import.
The problem of `load data infile optionally enclosed by` not working as expected can arise from three main causes. Firstly, PHP may incorrectly escape the enclosure character. In PHP, when generating an import query, an extra backslash before the double quote in a double-quoted string might be needed for PHP string validity, but MySQL does not require that same backslash in the SQL statement.
To confirm, print the actual query before executing it. Secondly, MySQL's CSV import might split a quoted field at a comma. For example, a CSV file containing `ABSOLUTE,Glenn,Anakie, Cool Synd, Super Cool` might not import properly. Before the opening quote, there might be an extra space: `ABSOLUTE,Glenn,Anakie, Cool Synd, Super Cool`.
MySQL does not automatically treat every quote found inside a field as an enclosing quote. The enclosure is recognized at the beginning of a field. Finally, changing the order of `TERMINATED BY` and `OPTIONALLY ENCLOSED BY` is not a general fix for malformed CSV files. Verify the actual field contents before making any changes.
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