The default initial value of one column in my database is the same as the row's auto-incremented id. I'm trying to use triggers to set it.
CREATE TRIGGER `default_order_value`
AFTER INSERT ON `clusters`
FOR EACH ROW
BEGIN
UPDATE `clusters` SET `order` = NEW.id WHERE `id` = NEW.id;
END
But this keeps throwing a syntax error
#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 5
I've tried all sorts of permutations of this with no luck. Can anyone see what I'm doing wrong?
As zerkms said, you need to change the delimeter. But since you only use 1 line of code, you don't need the BEGIN and END. And that way, you don't need to change the delimiter either
CREATE TRIGGER `default_order_value`
AFTER INSERT ON `clusters`
FOR EACH ROW
UPDATE `clusters` SET `order` = NEW.id WHERE `id` = NEW.id;
Since you are getting an error you cannot update the row, I suggest the following:
Do NOT perform the update query at all. On default the order value = the ID value. So when the order value changes, you can update it properly.
If you are requesting the data with php, do something like this:
$order = $row['order'];
if ($order == '')
$order = $row['id'];
After you need it updating, you've got the correct value.
I don't think you can do that. An AFTER INSERT trigger cannot modify the same table, neither by issuing an UPDATE nor by something like this:
CREATE TRIGGER `default_order_value`
AFTER INSERT ON `clusters`
FOR EACH ROW
SET NEW.`order` = NEW.id ;
which results in this error:
> Error Code: 1362. Updating of NEW row is not allowed in after trigger
You can't either use a BEFORE INSERT trigger because then the NEW.id is not known (if you modify the above, the order column will get 0 value after the Insert.
What you can do, is use a transaction:
START TRANSACTION ;
INSERT INTO clusters (id)
VALUES (NULL);
UPDATE clusters
SET `order` = id
WHERE id = LAST_INSERT_ID();
COMMIT ;
You get the error because mysql treats ; in line 5 as the end of your trigger declaration, which obviously leads to the syntax error.
So you need to redefine delimiter before you specify the trigger body:
delimiter |
CREATE TRIGGER `default_order_value`
AFTER INSERT ON `clusters`
FOR EACH ROW
BEGIN
UPDATE `clusters` SET `order` = NEW.id WHERE `id` = NEW.id;
END;
|
delimiter ;
You can create just BEFORE INSERT TRIGGER, it's works like this:
CREATE TRIGGER `default_order_value`
BeFORE INSERT ON `clusters`
FOR EACH ROW
BEGIN
SET NEW.`order` = NEW.id ;
END
same as below we are using
DELIMITER $$
USE `e_store`$$
DROP TRIGGER /*!50032 IF EXISTS */ `Test`$$
CREATE
/*!50017 DEFINER = 'root'#'%' */
TRIGGER `Test` BEFORE INSERT ON `categories`
FOR EACH ROW
BEGIN
DECLARE vtype VARCHAR(250) DEFAULT NULL;
SET vtype = NEW.name;
IF (NEW.MDNAME IS NULL)
THEN
-- SET NEW.MDNAME = 'NA';
SET NEW.MDNAME=MD5(NEW.name);
END IF;
END;
$$
DELIMITER ;
This worked for me:
CREATE TRIGGER `update_table_2`
AFTER UPDATE ON `table_1`
FOR EACH ROW
UPDATE table2
JOIN table_1
SET table_2.the_column = NEW.the_column
WHERE table_2.auto_increment_field = OLD.auto_increment_field
Related
I am trying to update a column ( called DateModified ) before update happens on the table row.
so here is my trigger:
CREATE TRIGGER `date_mod_category` BEFORE UPDATE ON `categories`
FOR EACH ROW BEGIN
SET new.DateModified = NOW();
END
BUT I GET THIS DAMN ERROR WHICH I JUST CANNOT FIGURE OUT WHY:
Use DELIMITER
DELIMITER //
CREATE TRIGGER `date_mod_category` BEFORE UPDATE ON `categories`
FOR EACH ROW
BEGIN
SET new.DateModified = NOW();
END //
DELIMITER ;
I have a table 'foods' with columns 'featured', 'restaurant_id', 'retaurant_stock'.
How can I update column 'restaurant_stock' using trigger or any other solution available on mySQL version 5.6 after update of column 'featured' on the same table on a condition?
Calculated columns are not available on mySQL version 5.6.
Here's my trigger:
CREATE TRIGGER update_restaurant_stock BEFORE UPDATE ON foods
OR EACH ROW
BEGIN
IF NEW.featured = 1 THEN
UPDATE `foods` SET NEW.restaurant_stock = (NEW.restaurant_id);
ELSE
UPDATE `foods` SET NEW.restaurant_stock = 0;
END IF;
END
Now when I update column 'featured' I get the following error message:
#1442 - Can't update table 'foods' in stored function/trigger because it is already used by statement which invoked this stored function/trigger.
Thanks for you help!
You can't update the current row that way, you can use set to change the new values
DELIMITER $$
CREATE TRIGGER update_restaurant_stock BEFORE UPDATE ON foods
OR EACH ROW
BEGIN
IF NEW.featured = 1 THEN
SET NEW.restaurant_stock = (NEW.restaurant_id);
ELSE
SET NEW.restaurant_stock = 0;
END IF;
END$$
DELIMITER ;
CREATE TRIGGER tr_bu_foods
BEFORE UPDATE
ON foods
FOR EACH ROW
-- update restaurant_stock
SET NEW.restaurant_stock = NEW.restaurant_id * (NEW.featured = 1);
I have a table with 4 columns [year, v_num, t_num, percentage], I'm trying to populate percentage with v_num/t_num*100. The data is already in the table but the percentage column is NULL. I created an AFTER INSERT trigger to populate the column but it's not working. Does anyone have any suggestions?
TRIGGER
DELIMITER |
CREATE DEFINER = 'XXX' TRIGGER percentAfterUp
AFTER INSERT
ON `table`
FOR EACH ROW
BEGIN
UPDATE `table` SET percentage = v_num/t_num*100;
END|
DELIMITER ;
If you want to set a value in a row, do it with a before insert trigger, not an after insert trigger:
DELIMITER |
CREATE DEFINER = 'XXX' TRIGGER percentAfterUp
BEFORE INSERT ON `table` FOR EACH ROW
BEGIN
SET new.percentage = (new.v_num / new.t_num) * 100;
END|
DELIMITER ;
If you actually want to update all the rows, don't use a trigger, just an update statement:
UPDATE `table`
SET percentage = (v_num/t_num)*100;
I'm running an insert into a members table and when a new row is added I want to run a trigger to update the username field of the members table but it wont let me due to constraints due to possible deadlock situations.
DELIMITER //
CREATE TRIGGER tr_add_member
AFTER INSERT ON td_members
FOR EACH ROW BEGIN
IF mem_username = '' THEN
SET mem_username = CONCAT('user' , mem_id);
END IF;
END//
DELIMITER ;
I've tried using the OLD and NEW keywords but they don't work, I've removed the NEW and OLD keywords above but get the below error with this trigger.
ERROR 1193 (HY000): Unknown system variable 'mem_username'
Should I be calling a procedure from the trigger to do what I want it and just run a simple UPDATE statement from within the procedure?
You have to use BEFORE INSERT trigger, but not an AFTER INSERT.
And if mem_id is auto incremented primary key field, then find its
next auto increment value from information_schema.tables and use it.
Change your trigger code as follows:
DELIMITER //
DROP TRIGGER IF EXISTS tr_add_member //
CREATE TRIGGER tr_add_member
BEFORE INSERT ON td_members
FOR EACH ROW
BEGIN
DECLARE _mem_id INT DEFAULT 0;
IF length( trim( NEW.mem_username ) ) = 0 THEN
SELECT AUTO_INCREMENT INTO _mem_id
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME = 'td_members'
AND TABLE_SCHEMA = DATABASE();
SET NEW.mem_username = CONCAT( 'user', _mem_id );
END IF;
END;
//
DELIMITER ;
I am trying to implement the following trigger but I am getting a MySQL syntax error. The idea is that after each time the table is updated I want to set the updated 'valid' field to 0 if the 'banned' field has been changed to 1. Also is the logic below correct?
Create Trigger `customers` Before Update on `customers` for each row BEGIN
set new.valid = 0 WHERE new.banned = 1;
END;
Yes the trigger should be something as
delimiter //
Create Trigger `customers_update`
Before Update on `customers`
for each row
BEGIN
IF new.banned = 1
THEN set new.valid = 0 ;
END IF ;
END;//
As you can see I have used delimiter in the trigger which is needed for the trigger. There is a nice explanation of this here What does DELIMITER // do in a Trigger?