MySQL properly stores non-standard ASCII characters but when it compares them on the uniqueness it treats them as standard ASCII characters. For example, “o” (HEX code 0x6F) and “ó” (shown below as � having a HEX code 0xF3) can be stored as they are but are not unique: mysql> SHOW CREATE TABLE test; +———+—————————————————————————-+ | [...]
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