字符型日期转换日期型的非常数据定位与处理

 1   CREATE OR REPLACE EDITIONABLE FUNCTION FUN_STR_TO_DATE (I_STR VARCHAR2)
 2 return DATE is
 3    V_DATE DATE;
 4 begin
 5   V_DATE:= TO_DATE(I_STR,‘YYYY/MM/DD‘) ; --单一格式
 6   REturn V_DATE;
 7 EXCEPTION
 8   WHEN OTHERS THEN 
 9      select TO_DATE(‘99991231‘,‘YYYYMMDD‘) into V_DATE from dual;
10      return   V_DATE ;
11 end ;

 1   CREATE OR REPLACE EDITIONABLE FUNCTION FN_STR_TO_DATE (I_STR VARCHAR2)
 2 RETURN DATE IS
 3    V_DATE DATE;
 4 BEGIN
 5   if INSTR(I_STR,‘/‘) > 0 then 
 6      SELECT TO_DATE(I_STR,‘YYYY/MM/DD‘) INTO V_DATE FROM DUAL;
 7    elsif INSTR(I_STR,‘-‘) > 0 then 
 8      SELECT TO_DATE(I_STR,‘YYYY-MM-DD‘) INTO V_DATE FROM DUAL;
 9   else 
10     SELECT TO_DATE(I_STR,‘YYYYMMDD‘) INTO V_DATE FROM DUAL;
11   end if;--多种格式的日期
12   RETURN V_DATE;
13 EXCEPTION
14   WHEN OTHERS THEN 
15      SELECT TO_DATE(‘99991231‘,‘YYYYMMDD‘) INTO V_DATE FROM DUAL;
16      RETURN   V_DATE ;
17 END ;