为了与 MaxDB 兼容，这两个语句是相同的：For MaxDB compatibility these two statements are the same:

CREATE TABLE t1 (f1 CHAR(N) UNICODE);
CREATE TABLE t1 (f1 CHAR(N) CHARACTER SET ucs2);

UNICODE 属性和 ucs2 字符集都已被弃用；你应该预期它们将在未来的 MySQL 版本中被移除。Both the UNICODE attribute and the ucs2 character set are deprecated; you should expect them to be removed in a future version of MySQL.