MySQL: char_length(), wrong value for Russian

Question

I am using char_length() to measure the size of "Русский": strangely, instead of telling me that it's 7 chars, it tells me there are 14. Interestingly if the query is simply...

SELECT CHAR_LENGTH('Русский')

...the answer is correct. However if I query the DB instead, the anser is 14:

SELECT CHAR_LENGTH(text) FROM locales WHERE lang = 'ru-RU' AND name = 'lang_name'

Anybody go any ideas what I might be doing wrong? I can confirm that the collation is utf8_general_ci and the table is MyISAM

Thanks, Adrien

EDIT: My end objective is to be able to measure the lengths of records in a table containing single and double-byte chracters (eg. English & Russian, but not limited to these two languages only)

Answer 1

Because of two bytes is used for each UTF8 char. See http://dev.mysql.com/doc/refman/5.5/en/string-functions.html#function_char-length

mysql> set names utf8;
mysql> SELECT CHAR_LENGTH('Русский'); result - 7
mysql> SELECT CHAR_LENGTH('test'); result  - 4

create table test123 (
text VARCHAR(255) NOT NULL DEFAULT '',
text_text TEXT) Engine=Innodb default charset=UTF8;

insert into test123 VALUES('русский','test русский');

SELECT CHAR_LENGTH(text),CHAR_LENGTH(text_text) from test123; result - 7 and 12

I have tested work with: set names koi8r; create table and so on and got invalid result. So the solution is recreate table and insert all data after setting set names UTF8.

Answer 2

the function return it's anwser guided by the most adjacent charset avaiable
in the case of a column, the column definition
in the case of a literal, the connection default
review the column charset with:

SELECT CHARACTER_SET_NAME FROM information_schema.`COLUMNS` 
where table_name = 'locales'
and column_name = 'text'

be careful, it is not filtered by table_schema