北辰孤星

摘要： select abs(-100) from dual;select mod(22,3 ) from dual;select ceil(12.0)from dual; select floor(12.5)from dual;select round(12.445 ,2) from dual; --截... 阅读全文

摘要： select * from t_hq_ryxx;select bianh,xingm from t_hq_ryxx;--as 指定别名select bianh as 编号, xingm as 姓名 from t_hq_ryxx t;select bianh 编号 from t_hq_ryxxsele... 阅读全文