How to print record that caused ORA-01843 error? - sql

Question

I have a table with millions of records. I am trying to format one column data to DATE format
which is currently in VARCHAR2. But, I am getting ORA-01843 not a valid month error.
I am trying to get those records which are causing ORA-01843
CREATE OR REPLACE PROCEDURE pr_TEST_CUSTOM_ORA1843 AS
v_company MyTable.MyColumn%TYPE;
BEGIN
BEGIN
SELECT to_char(to_date(TRIM(MyColumn), 'YYMMDD'), 'MM/DD/YYYY')
INTO v_company FROM MyTable;
EXCEPTION
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE('ORA-01843 caused by'||v_company);
END;
END pr_TEST_CUSTOM_ORA1843;
But, the value of v_company is not printed.
How to get the records which are causing ORA-01843 error?

Answer 1

I just commented on your previous question : How to format only those records for which ORA-01843 is not thrown? but you did not pay attention to it.
Create a function which checks if it is a valid date like this.
CREATE OR REPLACE FUNCTION validmmddyyyy (p_str IN VARCHAR2)
RETURN NUMBER
AS
V_date DATE;
BEGIN
V_Date := TO_DATE (p_str, 'MM/DD/YYYY');
RETURN 1;
EXCEPTION
WHEN OTHERS
THEN
RETURN 0;
END;
Then, to select the records which fail, you can run a query
select MyColumn FROM MyTable where validmmddyyyy(MyColumn) = 0
When you are lucky enough to use Oracle 12c R2, you could make use of DEFAULT..ON..CONVERSION ERROR clause of TO_DATE
SELECT *
FROM MyTable
WHERE TO_DATE (MyColumn default null on conversion error,'MM/DD/YYYY') IS NULL
An important advice as always, don't use a VARCHAR2 / CHAR type for DATEs in database.