Recipe 10.4. Dealing with Quotes and Special Characters

Problem

Your datafile contains quoted values or escaped characters.

Solution

Tell LOAD DATA to be aware of quote and escape characters so that it doesn't load data values into the database uninterpreted.

Discussion

The FIELDS clause can specify other format options besides TERMINATED BY. By default, LOAD DATA assumes that values are unquoted, and it interprets the backslash (\) as an escape character for special characters. To indicate the value-quoting character explicitly, use ENCLOSED BY; MySQL will strip that character from the ends of data values during input processing. To change the default escape character, use ESCAPED BY.

The three subclauses of the FIELDS clause (ENCLOSED BY, ESCAPED BY, and TERMINATED BY) may be present in any order if you specify more than one of them. For example, these FIELDS clauses are equivalent:

FIELDS TERMINATED BY ',' ENCLOSED BY '"' FIELDS ENCLOSED BY '"' TERMINATED BY ',' 

The TERMINATED BY sequence can consist of multiple characters. If data values are separated within input lines by something like *@*, you indicate that like this:

FIELDS TERMINATED BY '*@*' 

To disable escape processing entirely, specify an empty escape sequence:

FIELDS ESCAPED BY '' 

When you specify ENCLOSED BY to indicate which quote character should be stripped from data values, it's possible to include the quote character literally within data values by doubling it or by preceding it with the escape character. For example, if the quote and escape characters are " and \, the input value "a""b\"c" is interpreted as a"b"c.

For mysqlimport, the corresponding command options for specifying quote and escape values are --fields-enclosed-by and --fields-escaped-by. (When using mysqlimport options that include quotes or backslashes or other characters that are special to your command interpreter, remember that you may need to quote or escape the quote or escape characters.)