MySQL: Why is my trigger never adding 7 days? - mysql

Question

My table:
CREATE TABLE `files_processed` (
`filename` varchar(128) NOT NULL,
`uploaded_by` varchar(64) NOT NULL,
`domain` varchar(255) NOT NULL,
`session_id` varchar(64) NOT NULL,
`datetime_uploaded` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
`insert_data` tinyint(1) NOT NULL DEFAULT '1',
`generate_positives` tinyint(1) DEFAULT '1',
`generate_negatives` tinyint(1) NOT NULL DEFAULT '0',
`custom_rules` tinyint(1) NOT NULL DEFAULT '0',
`processing_stage` enum('completed','underway','wait','') NOT NULL DEFAULT 'wait',
`scheduled_processing_datetime` datetime DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
My trigger:
DELIMITER $$
CREATE TRIGGER `setProcessingData` BEFORE INSERT ON `files_processed` FOR EACH ROW BEGIN
DECLARE vNextDtTime datetime;
DECLARE vDom varchar(255);
SET vDom = new.domain;
SET new.session_id=new.domain;
SELECT max(scheduled_processing_datetime)
INTO vNextDtTime
FROM files_processed
WHERE domain='#vDom';
IF (ISNULL(vNextDtTime))
THEN
SET vNextDtTime := now();
ELSE
SET vNextDtTime := DATE_ADD(vNextDtTime, interval 7 day);
END IF;
SET new.scheduled_processing_datetime := vNextDtTime;
END
$$
DELIMITER ;
My 2 inserts:
INSERT INTO files_processed (filename, uploaded_by, domain)
VALUES ('1.txt', 'hcs.dfc#gmail.com', 'gmail.com');
Above is inserting current timestamp which is as expected
INSERT INTO files_processed (filename, uploaded_by, domain)
VALUES ('2.txt', 'hcs.dfc#gmail.com', 'gmail.com');
Now for this above, I expect the trigger to add 7 days, but it is still treating as current timestamp.

Answer 1

vDom is not equal to #vdom
If you put in the variable it works
# variables are session variables, that can be set and beselected after your insert.
Another think it is better to name a variable _vDom so that you know even in bigger triggers that is a local variable
DROP TRIGGER IF EXISTS `setProcessingData`;
DELIMITER $$
CREATE TRIGGER `setProcessingData` BEFORE INSERT ON `files_processed` FOR EACH ROW BEGIN
DECLARE vNextDtTime datetime;
DECLARE vDom varchar(255);
SET vDom = new.domain;
SET new.session_id=new.domain;
SELECT max(scheduled_processing_datetime)
INTO vNextDtTime
FROM files_processed
WHERE domain= vDom;
IF (ISNULL(vNextDtTime))
THEN
SET vNextDtTime := now();
ELSE
SET vNextDtTime := DATE_ADD(vNextDtTime, interval 7 day);
END IF;
SET new.scheduled_processing_datetime := vNextDtTime;
END
$$
DELIMITER ;