•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). 

The MySQL cp932  character set is designed to solve these problems. 

Because MySQL supports character set conversion, it is important to separate IANA Shift_JIS  and cp932  into two different character sets because they provide different conversion rules. 

## How does cp932  differ from sjis ? 

The cp932  character set differs from sjis  in the following ways: 

• 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: 

•If the character is in both JIS X 0208 and NEC special characters, use the code point of JIS X 0208. 

•If the character is in both NEC special characters and IBM selected characters, use the code point of NEC special characters. 

•If the character is in both IBM selected characters and NEC selected—IBM extended characters, use the code point of IBM extended characters. 

The table shown at https://msdn.microsoft.com/en-us/goglobal/cc305152.aspx 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: 

•NEC special characters (lead byte 0x87 ): 

https://msdn.microsoft.com/en-us/goglobal/gg674964 

•NEC selected—IBM extended characters (lead byte 0xED  and 0xEE ): 

https://msdn.microsoft.com/en-us/goglobal/gg671837 https://msdn.microsoft.com/en-us/goglobal/gg671838 

•IBM selected characters (lead byte 0xFA , 0xFB , 0xFC ): 

https://msdn.microsoft.com/en-us/goglobal/gg671839 https://msdn.microsoft.com/en-us/goglobal/gg671840 https://msdn.microsoft.com/en-us/goglobal/gg671841 

