Date datatype in source and destinattion. But format is different in source

Question

Hi
I have a proc that loads data from source table to destination table.
In the source table, I see the date is stored as yyyy/mm/dd. When i try to load from this source to destination, I get the following error:
SQLCODE -1861 SQLERRM ORA 01861 Literal string does not match the format string.Is there a way that I load from source to destination irrespective of the way date format used in source?
I cant do :
insert into destinationtable(datecol)
(select date1 from sourcetable)I get the above mentioned error.
Any help???

Answer 1

Hi,
So date1 is a VARCHAR2 column, that's supposed to represent a date in 'yyyy/mm/dd' format, but sometimes contains text that is not in that format: is that the problem?
Here's a package function I've used for similar problems:
--          **   t o _ d t   **
--          to_dt attempts to convert in_txt to a DATE using in_fmt_1_txt.
--          If that fails, it tries again, using in_fmt_2_txt.
--          If that fails, it tries again, using in_fmt_3_txt, and so on.
--          As soon as one conversion works, the function returns the DATE,
--          and the remaining formats are not tried.
--          If all the formats given fail, then NULL is returned.
FUNCTION     to_dt
(     in_txt          VARCHAR2                    -- string to be converted
,     in_fmt_1_txt     VARCHAR2     DEFAULT     'DD-Mon-YYYY'     -- 1st format to try
,     in_fmt_2_txt     VARCHAR2     DEFAULT NULL          -- 2nd format to try
,     in_fmt_3_txt     VARCHAR2     DEFAULT NULL          -- 3rd format to try
,     in_fmt_4_txt     VARCHAR2     DEFAULT NULL          -- 4th format to try
,     in_fmt_5_txt     VARCHAR2     DEFAULT NULL          -- 5th format to try
RETURN     DATE
DETERMINISTIC
IS
     fmt_cnt          PLS_INTEGER     := 5;          -- Number of in_fmt_ arguments
     fmt_num          PLS_INTEGER     := 1;          -- Number of argument being tried
     return_dt     DATE           := NULL;     -- To be returned
BEGIN
     WHILE     return_dt     IS NULL
     AND     fmt_num      <= fmt_cnt
     LOOP
          BEGIN     -- Block to trap conversion errors
               return_dt := TO_DATE ( in_txt
                                   , CASE     fmt_num
                                          WHEN  1     THEN  in_fmt_1_txt
                                          WHEN  2     THEN  in_fmt_2_txt
                                          WHEN  3     THEN  in_fmt_3_txt
                                          WHEN  4     THEN  in_fmt_4_txt
                                          WHEN  5     THEN  in_fmt_5_txt
                                END
          EXCEPTION
               WHEN OTHERS
               THEN
                    NULL;
          END;     -- Block to trap conversion errors
          fmt_num := fmt_num + 1;
     END LOOP;
     RETURN     return_dt;
END     to_dt
;The best solution, though, is to clean up the source table.
Identify the rows where date1 is not in 'yyyy/mm/dd' format.
If you can figure out what the correct data should be, UPDATE to that value.
If you can't figure out what the correct data should be, UPDATE to NULL.