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复制mysql> select lower(DDD);            +--------------+| lower(DDD) |+--------------+|               ddd |+--------------+mysql> select upper(ddd);              +--------------+| upper(ddd) |+--------------+| DDD |+--------------+mysql> select lcase(DDD);              +--------------+| lcase(DDD) |+--------------+| ddd |+--------------+mysql> select ucase(ddd);            +--------------+| ucase(ddd) |+--------------+| DDD |+--------------+             1.2.3.4.5.6.      
作者:数据库