## 10.10.7.2 The gb18030 Character Set 

In MySQL, the gb18030  character set corresponds to the “Chinese National Standard GB 18030-2005: Information technology—Chinese coded character set” , which is the official character set of the People’s Republic of China (PRC). 

## Characteristics of the MySQL gb18030 Character Set 

•Supports all code points defined by the GB 18030-2005 standard. Unassigned code points in the ranges (GB+8431A439, GB+90308130) and (GB+E3329A36, GB+EF39EF39) are treated as ’ ? ’ (0x3F). Conversion of unassigned code points return ’ ? ’. 

•Supports UPPER and LOWER conversion for all GB18030 code points. Case folding defined by Unicode is also supported (based on CaseFolding-6.3.0.txt ). 

•Supports Conversion of data to and from other character sets. 

•Supports SQL statements such as SET NAMES . 

•Supports comparison between gb18030  strings, and between gb18030  strings and strings of other character sets. There is a conversion if strings have different character sets. Comparisons that include or ignore trailing spaces are also supported. 

•The private use area (U+E000, U+F8FF) in Unicode is mapped to gb18030 . 

•There is no mapping between (U+D800, U+DFFF) and GB18030. Attempted conversion of code points in this range returns ’ ? ’. 

•If an incoming sequence is illegal, an error or warning is returned. If an illegal sequence is used in CONVERT() , an error is returned. Otherwise, a warning is returned. 

•For consistency with utf8  and utf8mb4 , UPPER is not supported for ligatures. 

•Searches for ligatures also match uppercase ligatures when using the gb18030_unicode_520_ci collation. 

•If a character has more than one uppercase character, the chosen uppercase character is the one whose lowercase is the character itself. 

•The minimum multibyte length is 1 and the maximum is 4. The character set determines the length of a sequence using the first 1 or 2 bytes. 

## Supported Collations 

• gb18030_bin : A binary collation. 

• gb18030_chinese_ci : The default collation, which supports Pinyin. Sorting of non-Chinese characters is based on the order of the original sort key. The original sort key is GB(UPPER(ch))  if UPPER(ch) exists. Otherwise, the original sort key is GB(ch) . Chinese characters are sorted according to the Pinyin collation defined in the Unicode Common Locale Data Repository (CLDR 24). Non-Chinese characters are sorted before Chinese characters with the exception of GB+FE39FE39 , which is the code point maximum. 

• gb18030_unicode_520_ci : A Unicode collation. Use this collation if you need to ensure that ligatures are sorted correctly. 

## 10.10.8 The Binary Character Set 

