Unicode Character Sets | utf8mb4_unicode_ci | PAD SPACE | | utf8mb4_icelandic_ci | PAD SPACE | ... | utf8mb4_0900_ai_ci | NO PAD | | utf8mb4_de_pb_0900_ai_ci | NO PAD | | utf8mb4_is_0900_ai_ci | NO PAD | ... | utf8mb4_ja_0900_as_cs | NO PAD | | utf8mb4_ja_0900_as_cs_ks | NO PAD | | utf8mb4_0900_as_ci | NO PAD | | utf8mb4_ru_0900_ai_ci | NO PAD | | utf8mb4_ru_0900_as_cs | NO PAD | | utf8mb4_zh_0900_as_cs | NO PAD | | utf8mb4_0900_bin | NO PAD | +----------------------------+---------------+ Comparison of nonbinary string values ( CHAR ,  VARCHAR , and  TEXT ) that have a  NO PAD  collation differ from other collations with respect to trailing spaces. For example,  ’a’  and  ’a ’  compare as different strings, not the same string. This can be seen using the binary collations for  utf8mb4 . The pad attribute for  utf8mb4_bin  is  PAD SPACE , whereas for  utf8mb4_0900_bin  it is  NO PAD . Consequently, operations involving  utf8mb4_0900_bin  do not add trailing spaces, and comparisons involving strings with trailing spaces may differ for the two collations: mysql>  CREATE TABLE t1 (c CHAR(10) COLLATE utf8mb4_bin); Query OK, 0 rows affected (0.03 sec) mysql>  INSERT INTO t1 VALUES(’a’); Query OK, 1 row affected (0.01 sec) mysql>  SELECT * FROM t1 WHERE c = ’a ’; +------+ | c | +------+ | a | +------+ 1 row in set (0.00 sec) mysql>  ALTER TABLE t1 MODIFY c CHAR(10) COLLATE utf8mb4_0900_bin; Query OK, 0 rows affected (0.02 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql>  SELECT * FROM t1 WHERE c = ’a ’; Empty set (0.00 sec) MySQL implements language-specific Unicode collations if the ordering based only on the Unicode Collation Algorithm (UCA) does not work well for a language. Language-specific collations are UCA-based, with additional language tailoring rules. Examples of such rules appear later in this section. For questions about particular language orderings, unicode.org provides Common Locale Data Repository (CLDR) collation charts at http://www.unicode.org/cldr/charts/30/collation/index.html. For example, the nonlanguage-specific  utf8mb4_0900_ai_ci  and language-specific utf8mb4_ LOCALE _0900_ai_ci  Unicode collations each have these characteristics: •The collation is based on UCA 9.0.0 and CLDR v30, is accent-insensitive and case-insensitive. These characteristics are indicated by  _0900 ,  _ai , and  _ci  in the collation name. Exception: utf8mb4_la_0900_ai_ci  is not based on CLDR because Classical Latin is not defined in CLDR. •The collation works for all characters in the range [U+0, U+10FFFF]. •If the collation is not language specific, it sorts all characters, including supplementary characters, in default order (described following). If the collation is language specific, it sorts characters of the Language-Specific Collations 1972