摘要： 隐式转换select * from emp where empno='7788'字符(char,varchar2)转换为数字(number)或日期(date)数字或日期转换为字符显式转换字符转换为数字或日期(TO_NUMBER, TO_DATE)数字或日期转换为字符(TO_CHAR)TO_CHAR(date, 'format_model')select sysdate, to_char(sysdate,'yyyy') yyyy, to_char(sysdate,'year') year,from dual;select sysda 阅读全文