Does the MySQL TRIM function not trim line breaks or carriage returns?

问题

From my experiments, it does not appear to do so. If this is indeed true, what is the best method for removing line breaks? I'm currently experimenting with the parameters that TRIM accepts of the character to remove, starting with trimming \n and \r.

回答1:

Trim() in MySQL only removes spaces.

I don't believe there is a built-in way to remove all kinds of trailing and leading whitespace in MySQL, unless you repeatedly use Trim().

I suggest you use another language to clean up your current data and simply make sure your inputs are sanitized from now on.

回答2:

My line breaks were in the middle of the string, and I didn't have control over the source data. The following mysql command worked for me:

REPLACE(FIELD,'\r\n',' ')

回答3:

Yes, Trim() will work in MySQL. You have two choices.

1) select it out:

select trim(BOTH '\n' from [field_name]) as field

If that doesn't work, try '\r', if that doesn't work, try '\n\r'.

2) replace the bad data in your table with an update...

update [table_name] set [field_name] = trim(BOTH '\n' from [field_name])

I recommend a select first to determine which line break you have (\r or \n).

回答4:

The standard MySQL trim function is not like trim functions in any other languages I know as it only removes exact string matches, rather than any characters in the string. This stored function is more like a normal trim you'd find in PHP, or strip in python etc.

CREATE FUNCTION `multiTrim`(string varchar(1023),remove varchar(63)) RETURNS varchar(1023) CHARSET utf8
BEGIN
  -- Remove trailing chars
  WHILE length(string)>0 and remove LIKE concat('%',substring(string,-1),'%') DO
    set string = substring(string,1,length(string)-1);
  END WHILE;

  -- Remove leading chars
  WHILE length(string)>0 and remove LIKE concat('%',left(string,1),'%') DO
    set string = substring(string,2);
  END WHILE;

  RETURN string;
END;

You should then be able to do:

select multiTrim(string,"\r\n\t ");

and it should remove all newlines, tabs and spaces.

回答5:

select trim(both '\r\n' from FIELDNAME) from TABLE; should work if select trim(both '\n' from FIELDNAME) from TABLE; doesn't work.

回答6:

select trim(both '\n' from FIELDNAME) from TABLE;

回答7:

i could only get it to work by making the char;

trim(both char(13) from fieldname)

回答8:

The answers above, when combined, work. A full example of replacing linebreaks at the beginning and end of the field looks like this:

UPDATE table SET field=REPLACE(field, field, TRIM(BOTH '\r\n' FROM field))

回答9:

I faced the same issue with one of the fields. There is no perfect solution. In my case i was lucky that the length of the field was supposed to be 6. So i used a query like

update events set eventuniqueid = substring(eventuniqueid, 1, 6) where length(eventuniqueid) = 7;

You will just have to choose the best option based on your need. The replace '\n' and '\r\n' did not work for me and just ended up wasting my time.

回答10:

REPLACE(FIELD,'\r\n',' ') works perfectly on MySql 5.1 database

来源：https://stackoverflow.com/questions/281724/does-the-mysql-trim-function-not-trim-line-breaks-or-carriage-returns

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mysql

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trim