oracle lpad函数

1在oracle 的数据库里有个函数 LPAD (String a,int length,String addString).

              2作用：把addString添加到a的左边，length 是返回值的长度。

               3例子

                  A ： SQL> select lpad ('test',8,0) from dual;

                LPAD ('TEST',8,0)
                    ----------------
                 0000test

               B： select lpad ('test',8) from dual;

              LPAD ('TEST',8)
                         --------------
               test 注：不写最后一个参数，函数会默认在返回值左边加一个空格。

               C： SQL> select lpad ('test',2,0) from dual;

                LPAD ('TEST',2,0)
                ----------------
              te

              D：SQL> select lpad ('test',3) from dual;

                   LPAD ('TEST',3)
                  --------------
                    tes