I have a table called sum_test with id,a,b,c fields
I need a trigger that calculates the sum of a+b on c but Im new to triggers.
How can I do that on Mysql?
CREATE TRIGGER `example` AFTER INSERT ON `sum_test`
FOR EACH ROW BEGIN
UPDATE sum_test
SET c= (a+b)
WHERE id = id
END
If we are wanting to set column c on the row we are inserting, then we can do like this, in a BEFORE insert trigger:
DELIMITER $$
CREATE TRIGGER `sum_test_bi` BEFORE INSERT ON `sum_test`
FOR EACH ROW
BEGIN
SET NEW.c = NEW.a + NEW.b ;
END$$
DELIMITER ;
I don't understand the reference to table suma. What does that table have to do with anything? We note that the condition id = id is going to evaluate to TRUE for every row in the table where id IS NOT NULL.
Related
I am trying to write an MYSQL statement that will copy the patient_id where they have a value of "Dose: Second" and paste it to my table vaccinatedpatients.
Also, I wanted to implement this within a trigger to automatically update itself after each new record on the table.
Any help with this will be great!
CREATE DEFINER=`root`#`localhost` TRIGGER `patient_AFTER_INSERT` AFTER INSERT ON `patient` FOR EACH ROW BEGIN
SELECT #variable = patient_id from patient where vaccine_Dose = 'Dose: Second';
INSERT INTO vaccinatedpatients VALUES(variable);
END
You can use an IF cLause, to determines if the patient gets the second dose
DELIMITER &&
CREATE DEFINER=`root`#`localhost` TRIGGER `patient_AFTER_INSERT` AFTER INSERT ON `patient` FOR EACH ROW
BEGIN
IF NEW.vaccine_Dose = 'Dose: Second' THEN
INSERT INTO vaccinatedpatients VALUES (NEW.patinet_id);
END IF;
END&&
DELIMITER ;
The DELIMITER may not be needed.
I have two tables A and B in mysql database. Table A having brnd_id, R_2000ml. Table B having diff,val. I am writing a trigger to update table B when R_2000ml is updated. I am calculating the difference of NEW.R_2000ml and OLD.R_2000ml and going to store the result in diff column and passing a boolean value as 1 to get updated in val column of table B.
Below is my trigger code which is not working as the values are not getting updated in table B.
DELIMITER //
DROP TRIGGER IF EXISTS `myTrigger`;
CREATE DEFINER=`root`#`localhost` TRIGGER `myTrigger`
AFTER UPDATE ON `A`
FOR EACH ROW
BEGIN
DECLARE brndid integer;
DECLARE stkdate date;
if NEW.`R_2000ml` <=> OLD.`R_2000ml`
THEN
if NEW.`R_2000ml` > OLD.`R_2000ml`
THEN
update B set diff= NEW.R_2000ml- OLD.R_2000ml,val=1;
END IF;
END IF;
END;//
DELIMITER ;
In your if clause you use "<=>", This operator performs an equality comparison like the = operator, so you should use <> or !=:
if NEW.`R_2000ml` <> OLD.`R_2000ml`
or
if NEW.`R_2000ml` != OLD.`R_2000ml`
I have create a trigger where the first column and second column would be concatenated into 3rd column.
USE `customer_1`;
DELIMITER $$
CREATE DEFINER=`root`#`%` TRIGGER `Metric1_anpr_vega_BINS` BEFORE INSERT ON `Metric1_anpr_vega` FOR EACH ROW
BEGIN
SET NEW.image_id = CONCAT(NEW.camera_id,'-', NEW.id);
END
Id camera_id image_id
4567 236 236-0
( here i can't get id of the row when triggered it is '0' instead of 4567)
what trigger would get the ID value in image_Id after insert statment exceuted.
If i use after insert I get this error - Updating of NEW row is not allowed in after trigger
USE `customer_1`;
DELIMITER $$
CREATE DEFINER=`root`#`%` TRIGGER `Metric1_anpr_vega_BINS` AFTER INSERT ON `Metric1_anpr_vega` FOR EACH ROW
BEGIN
SET NEW.image_id = CONCAT(NEW.camera_id,'-', NEW.id);
END
Here I want to copy the contents of X table into Y table and on the same lines I wanted to delete the row from X table.I tried it in following way but it is not working.
Drop trigger if exists myTrigger;
delimiter |
create trigger myTrigger
after insert on X
for each row
BEGIN
IF STRCMP(NEW.SysLogTag,"kernel:") = 0 THEN
INSERT INTO Y(logtime,moduleid,severity,messageid,message) values(NULL,1,1,100,NEW.Message);
ELSEIF NEW.SysLogTag like 'ntpd[%]:' THEN
INSERT INTO Y(logtime,moduleid,severity,messageid,message) values(NULL,6,1,100,NEW.Message);
ELSE
INSERT INTO Y(logtime,moduleid,severity,messageid,message) values(NULL,4,1,100,NEW.Message);
END IF;
delete from X where ID=NEW.ID; //Not working.
END;|
delimiter ;
From http://dev.mysql.com/doc/refman/5.1/en/create-trigger.html#c8808 :
My solution was to create a unique/primary key on the table I want to insert into (in this case on S_ID), then if my sanity check fails I change the s_id to 0. This method will only ever create one duff record with an s_id of 0. Obviously you need to INSERT ignore!
CREATE TRIGGER sanityCheck
BEFORE INSERT ON my_table
FOR EACH ROW
BEGIN
IF something THEN
SET NEW.S_ID = 0 ;
END IF;
END;
I'm not good at triggers in databases
Trigger:
delimiter $$
CREATE
DEFINER=`root`#`localhost`
TRIGGER `bon_apetite`.`orders_insert_update_trigger`
AFTER INSERT ON `bon_apetite`.`orders`
FOR EACH ROW
BEGIN
update budget_tracking set new.monthly_balance = old.monthly_balance + new.total_price
where tracking_userid = new.order_userid;
END
$$
tables:
budget_tracking and orders
columns:
budget_tracking (id,budget_userid,monthly_balance,created_date,modified_date)
orders(order_id,order_userid,total_price,created_date,modified_date)
budget_userid and order_userid are foriegn keys to a primary key in another table.
All I want is when I'm inserting values to orders table a trigger should update the monthly_balance field of budget_tracking table along with created_date and modified_date of both the tables.
Any help will be appreciated!
Try this
BEGIN
update budget_tracking set monthly_balance = monthly_balance + new.total_price
where tracking_userid = new.order_userid;
END
Try this:
DELIMITER $$
CREATE DEFINER=`root`#`localhost` TRIGGER `bon_apetite`.`orders_insert_update_trigger` AFTER INSERT ON `bon_apetite`.`orders` FOR EACH ROW
BEGIN
UPDATE budget_tracking SET monthly_balance = monthly_balance + new.total_price
WHERE tracking_userid = new.order_userid;
END$$
DELIMITER ;