oracle怎么在数据前面补0

Question

我从一个表里面提取出的DAY字段是1-31
现在我需要把DAY和MONTH合并在一起 但是DAY小于10前面需要补零
我用0||DAY 类型不符合..求高人指点.

Answer 1

select lpad(day,2,'0') from dual;

Answer 2

select lpad(day,2,'0') from tb_name;

Answer 3

scott@RACDB> select lpad('luoyoumou',14,'0') from dual;LPAD('LUOYOUMOU',14,'0')
----------------------------
00000luoyoumou

Answer 4

我那个是NUMBER型的  类型不能改变啊。

Answer 5

eygle@SZTYORA> select * from emp;     EMPNO ENAME                JOB                       MGR HIREDATE                   SAL       COMM     DEPTNO LOC
---------- -------------------- ------------------ ---------- ------------------- ---------- ---------- ---------- ---------------------
      7499 ALLEN                SALESMAN                 7698 1981-02-20 00:00:00       1600        300         30 CHICAGO
      7521 WARD                 SALESMAN                 7698 1981-02-22 00:00:00       1250        500         30 CHICAGO
      7654 MARTIN               SALESMAN                 7698 1981-09-28 00:00:00       1250        400         30 CHICAGO
      7844 TURNER               SALESMAN                 7698 1981-09-08 00:00:00       1500          0         30 CHICAGO
      7900 JAMES                CLERK                    7698 1981-12-03 00:00:00        950            30 CHICAGO
      7369 SMITH                CLERK                    7902 1980-12-17 00:00:00        800            20 DALLAS已选择6行。eygle@SZTYORA> select lpad(sal,15,'0') from emp;LPAD(SAL,15,'0')
------------------------------------------------------------------------------------------------------------------------
000000000001600
000000000001250
000000000001250
000000000001500
000000000000950
000000000000800已选择6行。eygle@SZTYORA>

Answer 6

eygle@SZTYORA> desc emp;
 名称                                                                                      是否为空? 类型
 ----------------------------------------------------------------------------------------- -------- -----------------------------
 EMPNO                                                                                     NOT NULL NUMBER(4)
 ENAME                                                                                              VARCHAR2(10)
 JOB                                                                                                VARCHAR2(9)
 MGR                                                                                                NUMBER(4)
 HIREDATE                                                                                           DATE
 SAL                                                                                                NUMBER(7,2)
 COMM                                                                                               NUMBER(7,2)
 DEPTNO                                                                                    NOT NULL NUMBER(2)
 LOC                                                                                       NOT NULL VARCHAR2(13)

Answer 7

-- 你指的类型不能改，是什么意思？
-- 首先：select 语句，不会修改你的表的类型，只是一种显示形式！
-- 如果你是说显示出来的必需是数值类型，但要有前导0，我想：无法实现！