10.10.7.2 The 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.

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.