MySQL automatically converts character sets.

Character sets are converted using Unicode (ucs2).

The sjis character set does not support the conversion of these extension characters.

There are several conversion rules from so-called “SHIFT JIS” to Unicode, and some characters are converted to Unicode differently depending on the conversion rule. MySQL supports only one of these rules (described later).

cp932 supports NEC special characters, NEC selected—IBM extended characters, and IBM selected characters.

Some cp932 characters have two different code points, both of which convert to the same Unicode code point. When converting from Unicode back to cp932, one of the code points must be selected. For this “round trip conversion,” the rule recommended by Microsoft is used. (See http://support.microsoft.com/kb/170559/EN-US/.)

The conversion rule works like this:

The table shown at http://www.microsoft.com/globaldev/reference/dbcs/932.htm provides information about the Unicode values of cp932 characters. For cp932 table entries with characters under which a four-digit number appears, the number represents the corresponding Unicode (ucs2) encoding. For table entries with an underlined two-digit value appears, there is a range of cp932 character values that begin with those two digits. Clicking such a table entry takes you to a page that displays the Unicode value for each of the cp932 characters that begin with those digits.

The following links are of special interest. They correspond to the encodings for the following sets of characters:

cp932 supports conversion of user-defined characters in combination with eucjpms, and solves the problems with sjis/ujis conversion. For details, please refer to http://www.opengroup.or.jp/jvc/cde/sjis-euc-e.html.