oracle 转换函数

No.

函数名

含义

1

字符串 to_char(列 | 日期,格式)

将日期或数字按格式转为字符串

2

日期 to_date(列 | 字符串,格式)

将字符串按格式转为日期

3

数字 to_number(列 | 字符串)

将字符串转为数字

select to_char(sysdate,‘yyyy-mm-dd‘) from dual;

select to_char(sysdate,‘yyyy-mm-dd hh24:mi:ss‘) from dual;

select * from emp where to_char(hiredate,‘mm‘)=‘04‘;

select * from emp where to_char(hiredate,‘mm‘)=4; --自动转型

select to_char(‘4758475847583‘,‘9,9999,9999,9999‘) from dual;

select to_char(‘4758475847583‘,‘L9,999,999,999,999‘) from dual;

select to_date(‘2017-11-21‘,‘yyyy-mm-dd‘) from dual;

select to_number(‘12‘)+to_number(‘1‘) from dual;

select ‘12‘+‘1‘ from dual;