使用

select to_char(28000,'FM9.9EEEE')

可以得到 2.8E+04 这样的格式，不知道是否能够满足需求

规则上满足了，显示还是有些问题，还是基于

select to_char(28000,'FM9.9EEEE')

改写，1.12280313123×10¹³这种情况还需要自己改下

CREATE TABLE T2 (C1 VARCHAR(100));
INSERT INTO "SYSDBA"."T2" ("C1") VALUES ('28000');
INSERT INTO "SYSDBA"."T2" ("C1") VALUES ('1024');
INSERT INTO "SYSDBA"."T2" ("C1") VALUES ('1024000000000000000000000000000000000000000000000');
COMMIT;

 --创建函数 
CREATE OR REPLACE FUNCTION  INT1 (INT01 VARCHAR)
RETURN  VARCHAR
AS  
    T0 VARCHAR =(UNISTR('\2070'));
    T1 VARCHAR =(UNISTR('\2071'));
    T2 VARCHAR =(UNISTR('\2072'));
    T3 VARCHAR =(UNISTR('\2073'));
    T4 VARCHAR =(UNISTR('\2074'));
    T5 VARCHAR =(UNISTR('\2075'));
    T6 VARCHAR =(UNISTR('\2076'));
    T7 VARCHAR =(UNISTR('\2077'));
    T8 VARCHAR =(UNISTR('\2078'));
    T9 VARCHAR =(UNISTR('\2079'));
BEGIN
  SELECT  ( SELECT A1 ||'×10'|| REPLACE( REPLACE( REPLACE(REPLACE( REPLACE( REPLACE( REPLACE( REPLACE(REPLACE(REPLACE(A2, '0', T0), '1', T1), '2', T2), '3', T3), '4', T4) , '5', T5) , '6', T6) , '7', T7) , '8', T8), '9', T9)
      FROM ( SELECT A1, 
                   CASE WHEN SUBSTR(A2, 1, 1) = '0' THEN SUBSTR(A2, 2) ELSE A2 END AS A2
              FROM ( SELECT SUBSTR(TO_CHAR(INT01,'FM9.9EEEE'),1,(INSTR(TO_CHAR(INT01,'FM9.9EEEE'),'E'))-1) AS A1 ,
                           SUBSTR(TO_CHAR(INT01,'FM9.9EEEE'),(INSTR(TO_CHAR(INT01,'FM9.9EEEE'),'+'))+1) AS A2
                      FROM DUAL) T11))  INTO  INT01;
    RETURN INT01;
END;

 --返回结果
SELECT INT1(C1) FROM  T2  ;