Update PSQL Column with Default Date if erroneus date - sql

Question

I am using PostgreSQL 9.3 i have a column called appointment date in a table appointment which has erroneous dates like 21117-03-04 i wish to update all rows in the column to have a default date e.g. 1900-01-01 if the value on that column is any erroneous date. I have not yet tried any solution yet. please help.

Answer 1

you can use below procedure
DELIMITER $$
CREATE DEFINER=`root`#`localhost` PROCEDURE `MAKE_ACCURATE_DATE`()
BEGIN
DECLARE VAR_ID varchar(100);
DECLARE VAR_DATE DATE;
DECLARE VAR_FINISHED INT(11) DEFAULT 0;
DECLARE DATABASE_CURSOR CURSOR FOR
SELECT DATE(DATE_COLUMN) DATE_COLUMN,ID
FROM YOUR_TABLE_NAME;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET VAR_FINISHED = 1;
OPEN DATABASE_CURSOR;
GET_NEXTRECORD: LOOP
FETCH DATABASE_CURSOR INTO VAR_DATE,VAR_ID;
IF VAR_FINISHED = 1 THEN
LEAVE GET_NEXTRECORD;
END IF;
IF VAR_DATE =NULL THEN
UPDATE YOUR_TABLE_NAME SET DATE_COLUMN='1900-01-01' WHERE ID=VAR_ID;
END IF;
END LOOP GET_NEXTRECORD;
CLOSE DATABASE_CURSOR;
END$$
DELIMITER ;
OR
FOR POSTGRES
CREATE OR REPLACE FUNCTION IS_VALID_DATE(S VARCHAR) RETURNS BOOLEAN AS $$
BEGIN
PERFORM S::DATE;
RETURN TRUE;
EXCEPTION WHEN OTHERS THEN
RETURN FALSE;
END;
$$ LANGUAGE PLPGSQL;
And make change in above function as below.
CREATE OR REPLACE FUNCTION MAKE_ACCURATE_DATE()
RETURNS void AS
$BODY$
DECLARE
RECORD RECORD;
COUNT INT;
BEGIN
COUNT=0;
FOR RECORD IN SELECT * FROM cpad.dtl_patientappointment;
LOOP
IF(!IS_VALID_DATE(RECORD.appointmentdate)) THEN
UPDATE cpad.dtl_patientappointment SET appointmentdate='1900-01-01' WHERE patientappointmentid=RECORD.patientappointmentid;
END IF;
END LOOP;
END;
$BODY$
LANGUAGE plpgsql;
And execute this line
SELECT MAKE_ACCURATE_DATE();
It will fetch your record from table one by one and as
DATE(DATE_COLUMN) is there,it will returns null if date is not proper.So after applying condition it will update that record with specific ID.
Hope this will helps.