I am pulling data from database into R. I use the following commands to do this:
drv = dbDriver("MySQL")
con = dbConnect(drv,<credentials>)
dbSendQuery(con,"SET character_set_results = utf8;")
<code to pull data>
The data is stored in UTF-8 encoding in the database.I pull a dataframe with a column containing words. Once i pull the data, i convert the encoding to ASCII//TRANSLIT using iconv(x,"UTF-8","ASCII//TRANSLIT") Everything is working fine except that for few words i see an extra character appearing after i change the encoding. For example when u look in database you see abc and when u import, you get abc. But once you change the encoding to ASCII//TRANSLIT this word changes to abc?. I used https://www.branah.com/unicode-converter to check for encoding. I copied word abc in first box named unicode text and i see abc⬠in box named utf-8 text.What are these special characters and how to use them in regex to filter these out?
SET character_set_results = utf8 is probably not sufficient. Change to SET NAMES utf8mb4.
What do you mean by "pull the data"? Is it put into a database table? If so, please provide SHOW CREATE TABLE.
To investigate strange characters, do SELECT HEX(...) ... to see what is actually there. From that, we might be able to deduce what happened.
It looks like ⬠is part of the Mojibake for one of these.
⬀,⬁,⬂,⬃,⬄,⬅,⬆,⬇,⬈,⬉,⬊,⬋,⬌,⬍,⬎,⬏,⬐,⬑,⬒,⬓,⬔,⬕,⬖,⬗,⬘,⬙,⬚,⬛,⬜,⬝,⬞,⬟,⬠,⬡,⬢,⬣,⬤,⬥,⬦,⬧,⬨,⬩,⬪,⬫,⬬,⬭,⬮,⬯,⬰,⬱,⬲,⬳,⬴,⬵,⬶,⬷,⬸,⬹,⬺,⬻,⬼,⬽,⬾,⬿
â¬, when treated as latin1, is hex E2AC
⬀ when treated as UTF-8 (utf8mb4), is hex E2AC80
⬁ is hex E2AC81,
etc
The causes of Mojibake are discussed here.
Instead of trying to filter them out, you should fix the code to preserve them.
Related
I tried to use UTF-8 and ran into trouble.
I have tried so many things; here are the results I have gotten:
???? instead of Asian characters. Even for European text, I got Se?or for Señor.
Strange gibberish (Mojibake?) such as Señor or 新浪新闻 for 新浪新闻.
Black diamonds, such as Se�or.
Finally, I got into a situation where the data was lost, or at least truncated: Se for Señor.
Even when I got text to look right, it did not sort correctly.
What am I doing wrong? How can I fix the code? Can I recover the data, if so, how?
This problem plagues the participants of this site, and many others.
You have listed the five main cases of CHARACTER SET troubles.
Best Practice
Going forward, it is best to use CHARACTER SET utf8mb4 and COLLATION utf8mb4_unicode_520_ci. (There is a newer version of the Unicode collation in the pipeline.)
utf8mb4 is a superset of utf8 in that it handles 4-byte utf8 codes, which are needed by Emoji and some of Chinese.
Outside of MySQL, "UTF-8" refers to all size encodings, hence effectively the same as MySQL's utf8mb4, not utf8.
I will try to use those spellings and capitalizations to distinguish inside versus outside MySQL in the following.
Overview of what you should do
Have your editor, etc. set to UTF-8.
HTML forms should start like <form accept-charset="UTF-8">.
Have your bytes encoded as UTF-8.
Establish UTF-8 as the encoding being used in the client.
Have the column/table declared CHARACTER SET utf8mb4 (Check with SHOW CREATE TABLE.)
<meta charset=UTF-8> at the beginning of HTML
Stored Routines acquire the current charset/collation. They may need rebuilding.
UTF-8 all the way through
More details for computer languages (and its following sections)
Test the data
Viewing the data with a tool or with SELECT cannot be trusted.
Too many such clients, especially browsers, try to compensate for incorrect encodings, and show you correct text even if the database is mangled.
So, pick a table and column that has some non-English text and do
SELECT col, HEX(col) FROM tbl WHERE ...
The HEX for correctly stored UTF-8 will be
For a blank space (in any language): 20
For English: 4x, 5x, 6x, or 7x
For most of Western Europe, accented letters should be Cxyy
Cyrillic, Hebrew, and Farsi/Arabic: Dxyy
Most of Asia: Exyyzz
Emoji and some of Chinese: F0yyzzww
More details
Specific causes and fixes of the problems seen
Truncated text (Se for Señor):
The bytes to be stored are not encoded as utf8mb4. Fix this.
Also, check that the connection during reading is UTF-8.
Black Diamonds with question marks (Se�or for Señor);
one of these cases exists:
Case 1 (original bytes were not UTF-8):
The bytes to be stored are not encoded as utf8. Fix this.
The connection (or SET NAMES) for the INSERT and the SELECT was not utf8/utf8mb4. Fix this.
Also, check that the column in the database is CHARACTER SET utf8 (or utf8mb4).
Case 2 (original bytes were UTF-8):
The connection (or SET NAMES) for the SELECT was not utf8/utf8mb4. Fix this.
Also, check that the column in the database is CHARACTER SET utf8 (or utf8mb4).
Black diamonds occur only when the browser is set to <meta charset=UTF-8>.
Question Marks (regular ones, not black diamonds) (Se?or for Señor):
The bytes to be stored are not encoded as utf8/utf8mb4. Fix this.
The column in the database is not CHARACTER SET utf8 (or utf8mb4). Fix this. (Use SHOW CREATE TABLE.)
Also, check that the connection during reading is UTF-8.
Mojibake (Señor for Señor):
(This discussion also applies to Double Encoding, which is not necessarily visible.)
The bytes to be stored need to be UTF-8-encoded. Fix this.
The connection when INSERTing and SELECTing text needs to specify utf8 or utf8mb4. Fix this.
The column needs to be declared CHARACTER SET utf8 (or utf8mb4). Fix this.
HTML should start with <meta charset=UTF-8>.
If the data looks correct, but won't sort correctly, then
either you have picked the wrong collation,
or there is no collation that suits your need,
or you have Double Encoding.
Double Encoding can be confirmed by doing the SELECT .. HEX .. described above.
é should come back C3A9, but instead shows C383C2A9
The Emoji 👽 should come back F09F91BD, but comes back C3B0C5B8E28098C2BD
That is, the hex is about twice as long as it should be.
This is caused by converting from latin1 (or whatever) to utf8, then treating those
bytes as if they were latin1 and repeating the conversion.
The sorting (and comparing) does not work correctly because it is, for example,
sorting as if the string were Señor.
Fixing the Data, where possible
For Truncation and Question Marks, the data is lost.
For Mojibake / Double Encoding, ...
For Black Diamonds, ...
The Fixes are listed here. (5 different fixes for 5 different situations; pick carefully): http://mysql.rjweb.org/doc.php/charcoll#fixes_for_various_cases
I had similar issues with two of my projects, after a server migration. After searching and trying a lot of solutions, I came across with this one:
mysqli_set_charset($con,"utf8mb4");
After adding this line to my configuration file, everything works fine!
I found this solution for MySQLi—PHP mysqli set_charset() Function—when I was looking to solve an insert from an HTML query.
I was also searching for the same issue. It took me nearly one month to find the appropriate solution.
First of all, you will have to update you database will all the recent CHARACTER and COLLATION to utf8mb4 or at least which support UTF-8 data.
For Java:
while making a JDBC connection, add this to the connection URL useUnicode=yes&characterEncoding=UTF-8 as parameters and it will work.
For Python:
Before querying into the database, try enforcing this over the cursor
cursor.execute('SET NAMES utf8mb4')
cursor.execute("SET CHARACTER SET utf8mb4")
cursor.execute("SET character_set_connection=utf8mb4")
If it does not work, happy hunting for the right solution.
Set your code IDE language to UTF-8
Add <meta charset="utf-8"> to your webpage header where you collect data form.
Check your MySQL table definition looks like this:
CREATE TABLE your_table (
...
) ENGINE=InnoDB DEFAULT CHARSET=utf8
If you are using PDO, make sure
$options = array(PDO::MYSQL_ATTR_INIT_COMMAND=>'SET NAMES utf8');
$dbL = new PDO($pdo, $user, $pass, $options);
If you already got a large database with above problem, you can try SIDU to export with correct charset, and import back with UTF-8.
Depending on how the server is setup, you have to change the encode accordingly. utf8 from what you said should work the best. However, if you're getting weird characters, it might help if you change the webpage encoding to ANSI.
This helped me when I was setting up a PHP MySQLi. This might help you understand more: ANSI to UTF-8 in Notepad++
How can one clean data that looks like this Réation, l’Oreal to look like this R'action and L'Oreal respectively in MySQL?
That looks like an example of "double encoding". It is where the right hand was talking utf8, but the left hand was listening for latin1. See Trouble with UTF-8 characters; what I see is not what I stored and See also http://mysql.rjweb.org/doc.php/charcoll#fixes_for_various_cases .
Réation -> Réation after undoing the double-encoding.
Yet you say R'action -- I wonder if you were typing é as e' or 'e??
I'm also going to assume you meant L’Oreal?? (Note the 'right single quote mark' instead of 'apostrophe'.)
First, we need to verify that it is actually an ordinary double-encoding.
SELECT col, HEX(col) FROM ... WHERE ...
should give you this for the hex for Réation:
52 E9 6174696F6E -- latin1 encoding
52 C3A9 6174696F6E -- utf8 encoding
52 C383 C2A9 6174696F6E -- double encoding
(Ignore the spacing.)
If you got the third of those proceed with my Answer. If you get anything else, STOP! -- the problem is more complex than I thought.
Now, see if the double-encoding fix will fix it (before fixing it):
SELECT col, CONVERT(BINARY(CONVERT(CONVERT(
BINARY(CONVERT(col USING latin1)) USING utf8mb4)
USING latin1)) USING utf8mb4)
FROM tbl;
You need to prevent it from happening and fix the data. Some of the following is irreversible; test it on a copy of the table!
Your case is: CHARACTER SET latin1, but have utf8/utf8mb4 bytes in it; leave bytes alone while fixing charset:
First, let's assume you have this declaration for tbl.col:
col VARCHAR(111) CHARACTER SET latin1 NOT NULL
Then to convert the column without changing the bytes:
ALTER TABLE tbl MODIFY COLUMN col VARBINARY(111) NOT NULL;
ALTER TABLE tbl MODIFY COLUMN col VARCHAR(111) CHARACTER SET utf8mb4 NOT NULL;
Note: If you start with TEXT, use BLOB as the intermediate definition. (Be sure to keep the other specifications the same - VARCHAR, NOT NULL, etc.)
Do that for each column in each table with the problem.
(In this discussion I don't distinguish between utf8mb4 and utf8. Most text is quite happy with either; Emoji and some Chinese need utf8mb4, not just utf8.)
from Comment
CONVERT(UNHEX('C38EC2B2') USING utf8mb4) = 'β' (Greek beta)
CONVERT(CONVERT(UNHEX('C38EC2B2') USING latin1) USING utf8mb4) = 'β'
My conclusion: First you had some misconfiguration. Then you applied one or more wrong fixes. You now have such a mess that I dare not try to help you unravel it. That is, the mess is on beyond simply "double encoding".
If possible, start over, being sure that some test data gets stored correctly before adding more data. If the data is bad not try to fix the data; back off and start over again. See the "best bractice" in "Trouble..." for getting set up correctly. I'll be around to help you interpret whether the hex you see in the tables is correct.
We have some tables that were set with the Latin character set instead of UTF-8 and it allowed bad characters to be entered into the tables, the usual culprit is people copy / pasting from Word or Outlook which copys those nasty hidden characters...
Is there any query we can use to identify these characters to clean them?
Thanks,
I assume that your connection chacater set was set to UTF8 when you filled the data in.
MySQL replaces unconvertable characters with ? (question marks):
SELECT CONVERT('тест' USING latin1);
----
????
The problem is distinguishing legitimate question marks from illegitimate ones.
Usually, the question marks in the beginning of a word are a bad sign, so this:
SELECT *
FROM mytable
WHERE myfield RLIKE '\\?[[:alnum:]]'
should give a good start.
You're probably noticing something like this 'bug'. The 'bad characters' are most likely UTF-8 control characters (eg \x80). You might be able to identify them using a query like
SELECT bar FROM foo WHERE bar LIKE LOCATE(UNHEX(80), bar)!=0
From that linked bug, they recommend using type BLOB to store text from windows files:
Use BLOB (with additional encoding field) instead of TEXT if you need to store windows files (even text files). Better than 3-byte UTF-8 and multi-tier encoding overhead.
Take a look at this Q/A (it's all about your client encoding aka SET NAMES )
Somewhere along the way, between all the imports and exports I have done, a lot of the text on a blog I run is full of weird accented A characters.
When I export the data using mysqldump and load it into a text editor with the intention of using search-and-replace to clear out the bad characters, searching just matches every "a" character.
Does anyone know any way I can successfully hunt down these characters and get rid of them, either directly in MySQL or by using mysqldump and then reimporting the content?
This is an encoding problem; the  is a non-breaking space (HTML entity ) in Unicode being displayed in Latin1.
You might try something like this... first we check to make sure the matching is working:
SELECT * FROM some_table WHERE some_field LIKE BINARY '%Â%'
This should return any rows in some_table where some_field has a bad character. Assuming that works properly and you find the rows you're looking for, try this:
UPDATE some_table SET some_field = REPLACE( some_field, BINARY 'Â', '' )
And that should remove those characters (based on the page you linked, you don't really want an nbsp there as you would end up with three spaces in a row between sentences etc, you should only have one).
If it doesn't work then you'll need to look at the encoding and collation being used.
EDIT: Just added BINARY to the strings; this should hopefully make it work regardless of encoding.
The accepted answer did not work for me.
From here http://nicj.net/mysql-converting-an-incorrect-latin1-column-to-utf8/ I have found that the binary code for  character is c2a0 (by converting the column to VARBINARY and looking what it turns to).
Then here http://www.oneminuteinfo.com/2013/11/mysql-replace-non-ascii-characters.html found the actual solution to remove (replace) it:
update entry set english_translation = unhex(replace(hex(english_translation),'C2A0','20')) where entry_id = 4008;
The query above replaces it to a space, then a normal trim can be applied or simply replace to '' instead.
I have had this problem and it is annoying, but solvable. As well as  you may find you have a whole load of characters showing up in your data like these:
“
This is connected to encoding changes in the database, but so long as you do not have any of these characters in your database that you want to keep (e.g. if you are actually using a Euro symbol) then you can strip them out with a few MySQL commands as previously suggested.
In my case I had this problem with a Wordpress database that I had inherited, and I found a useful set of pre-formed queries that work for Wordpress here http://digwp.com/2011/07/clean-up-weird-characters-in-database/
It's also worth noting that one of the causes of the problem in the first place is opening a database in a text editor which might change the encoding in some way. So if you can possibly manipulate the database using MySQL only and not a text editor this will reduce the risk of causing further trouble.
I have a table with a field which contains strings in my MySQL database.
The MySQL version is 5.0.51a. The default character set for the table is 'utf8'.
Many of the strings have unicode characters such as \xae and \u21222 (registered symbol and trademark symbol respectively).
For example, suppose I have a row with a field this value:
"Bing® Blang™ Blaow"
The default character set of my mysql command line client is "latin1".
If I issue a SELECT statement in the mysql client program from the command line without specifying a character set, the output of the title shows up like so:
"Bing® Blang Blaow"
The (R) symbol is correct but the (TM) symbol is missing. If I cut and paste this string from the console into TextMate, the (TM) symbol appears, but is half-way behind the g in the word "Blang".
I am assuming that the half-way-behind-the-g thing is a just a display error in TextMate (though if anyone can provide further detail that'd be great, but that's not really the important part).
The main thing I am inferring from the its-there-after-you-cut-and-paste behavior is that the data is in the database but there's something wrong with some sort of character set setting somewhere.
If I override the default encoding of the mysql client on the command line like so:
mysql --default-character-set=utf8
Then do the same select, the string comes out as:
"Bing® Blang™ Blaow"
which is to say that both the (R) and (TM) symbols appear and are in the right place but both are preceded by the unicode character \xae which is an A with a circumflex on top.
(Incidentally this is also how the data is displayed when I pull it out using python and display it on a web page, which is what my real problem is).
Anyway, what is going on here? Everything we have done recently has used UTF8 everywhere possible, but it's possible that some of these rows were inserted prior to that change which means they would've been using the latin1 default... however neither encoding seems to produce the right result?
If the rows were inserted when the default encoding on the table was latin1 before it was switched to utf8, then the encoding was switched (via alter table..) then would the encoding have actually been updated? Should one of the encodings work now? Will unicode ever stop kicking my ass?
There are quite a number of issues here:
About the characters
You indicate that the text has characters U+AE and U+2122 (® and ™ respectively). However, the results imply that the text has U+99 as the character after "Blang": When you set MySQL to output UTF8, then you see this "™" -- which is the UTF8 sequence for U+99 displayed on a terminal that is interpreting this byte stream as Windows-1252.
U+99 probably isn't what you wanted: In Unicode, that is an extended control character with no graphic representation. It just so happens that in Windows-1252, that 0x99 is the encoding of the trademark symbol (U+2122).
(Please note that both MySQL and most web browsers have a common, "broken" behavior of using Windows-1252 when you choose Latin1. Sigh.)
What's probably wrong
Your terminal isn't operating in the right character set. It is clearly operating in Windows-1252.
Programs should be connecting to the database in UTF-8. You can do that in the command line, as you've found, or by executing the statement SET NAMES utf8_general_ci; in your database handle before doing anything else. Some other database APIs may have other ways of doing this, but there is no generic way for all SQL engines. SET NAMES ... is specific to MySQL, but sets all the required character set variables (there are three!) at once.
The process that is inserting data into the database is taking user input and not correctly converting it from Windows-1252 into UTF-8 before inserting. This is how you got a U+99 into your database. Since I don't know how you are getting that data, I'm not sure what to fix, but here are several possibilities:
If the data comes from a web page form, be sure the page with the form is served in UTF-8, is properly marked as such (via the MIME Type, and the <meta> tag.) Be sure also, that the <form> tag is not specifying a different character set.
When converting the data, be sure that you use iconv or similar libraries to convert from the input character set to UTF-8. Even if you think the input is Latin1, do not try to do this by hand (for example, by zero expanding every byte to 16-bits then claiming this is UTF-16 - that won't work for Windwos-1252!). Make absolutely certain that you know the character set of the source data. In particular, be sure to know if it is Latin1 or Windows-1252.
Instead of converting the user input, you could connect to the database in character set of the user input, and then just insert the raw byte data you get from the user. However, you must be sure to only do insertions this way: reading back data from the data with the user's character set in effect will lose information if other rows have data that can't be represented in that character set. It is possible to set up a MySQL connection so that you issue statements in one character set and read results back in another... But it isn't for the faint of heart, and future programmers will likely go nuts trying to understand why the code does this.
If, when you pull the data out with Python and display it in a web page, you see the string "™", then that is indication that your are pulling the data out of the database correctly as UTF-8, but then putting it into a web page that is not correctly identified as UTF-8. Probably it is just defaulting to Latin1, which as noted above will really be Windows-1252.
Nonetheless, even if you fix the display, note that the data base has bad data in it, since U+99 isn't really the trademark symbol in a UTF-8 column. You'll need to clean up your data, by reading all the data, and replacing any characters in the range of U+80 through U+9F with what they were likely to have been, assuming the data was really Windows-1252. If you're not certain what character set the data was in originally -- then this data is, alas, just junk.
About changing character sets of tables
Converting the character set and collation of the table after inserting data will convert the columns, but, of course, any data already inserted will have already lost whatever characters the original character set couldn't represent.
Be careful to note the difference between ALTER TABLE foo CONVERT TO CHARACTER SET ... and ALTER TABLE foo CHARACTER SET ... The later only changes the default character set for the table, and will not change any columns, even if they were set to the default at creation. (MySQL only uses the defaults at column creation time, it doesn't remember that a given column is "defaulted" not does it keep it in sync with the table's default.)
I think it has to do with the settings of the mysql connection in your Python code.
try setting conn.character_set_name or something like that, depends on the mysql connection lib you are using.
in case of MySQLdb it should be smthng like this:
def character_set_name(*args, **kwargs): return 'utf-8'
conn.character_set_name = new.instancemethod(character_set_name, conn, conn.__class__)
Could it be that some of the columns have an explicitly different character set than the table default?
something like this...?
ALTER TABLE tbl_name CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci