I am trying to create a trigger in mysql using the following:
CREATE TRIGGER ins_daft BEFORE INSERT ON jos_ezrealty
FOR EACH ROW BEGIN
SET preschool = livingarea*10.76391041671
END;
When I do I get the following error:
Error
SQL query:
CREATE TRIGGER ins_daft BEFORE INSERT ON jos_ezrealty
FOR EACH
ROW BEGIN
SET preschool = livingarea * 10.76391041671 END
MySQL said: Documentation
#1193 - Unknown system variable 'preschool'
I am trying to have the value of one field converted to square feet by multiplying by 10.76391041671. Can anyone see what I am doing wrong?
Thank you.
Any time you want to reference the columns of a row that fired the trigger, qualify them like NEW.column_name.
Otherwise the SET command thinks you want to set a MySQL configuration variable called preschool.
Related
I'm new to the php mysql developpement, I want to make a trigger to be launched after I insert a row in the evolution table. The trigger must take a value (prixMisDaccord) from another table (inscription) and reduce it value from the evolution column prixAPaye.
Here is what I tried and what I found on Stack Overflow:
DELIMITER $$
CREATE TRIGGER trg_rap
BEFORE INSERT ON evolution FOR EACH ROW
BEGIN
DECLARE pmd float;
-- Check BookingRequest table
SELECT prixMisDaccord
INTO #pmd
FROM inscription
WHERE inscription.idETD= 1;
SET NEW.resteAPaye = #pmd-NEW.prixPaye
WHERE idETD = 1;
END;
$$
DELIMITER `;
'i have a probleme from this line SELECT' - Is not the error I get, I do get an error on the set statement because you cannot apply a where clause to a set..There are other problems with your code and you don't seem to know the difference between user defined variables and declared variables see - How to declare a variable in MySQL? and temporary tables..so #pmd-NEW.prixPaye is just nonsense.
If you want more help read https://stackoverflow.com/help/how-to-ask and provide table definitions,sample data and desired outcome all as text in the question.
I'm using SQLite 3.37.2 through Python 3.10.5, and editing the database with DBeaver - maybe it's not always at its best when reporting database errors.
Anyway, I want to convert a text (JSON) in SQLite proper JSON format upon insertion, by calling its json() function.
I thought about adding a simple trigger to handle that, but I can't figure out what's wrong in my syntax:
CREATE TRIGGER t1_before_insert AFTER INSERT ON t1 FOR EACH ROW
BEGIN
SET NEW.json:=json(NEW.json);
END
;
This is the latest version I attempted, I always get an error like
SQL error or missing database (near "SET": syntax error)
I tried:
SET NEW.json:=json(NEW.json)
SET NEW.json=json(NEW.json)
SELECT NEW.json:=json(NEW.json)
using an AFTER INSERT trigger
but none worked.
You can't change the value of a column of the new row like that.
You must update the table in an AFTER INSERT trigger:
CREATE TRIGGER t1_after_insert AFTER INSERT ON t1 FOR EACH ROW
BEGIN
UPDATE t1
SET json = json(NEW.json)
WHERE t1.id = NEW.id;
END;
Change id to the table's primary key.
See the demo.
I've been trying to create a MySQL Trigger in order to set a random value to a column called confcode which is used for authentication purposes.
The issue is, the value never sets after I insert a new row and keeps being empty.
I use phpMyAdmin to create the trigger, and these are the defines:
Trigger name: confcode
Table: ebaysales
Time: BEFORE/AFTER (both don't work)
Event: INSERT
Definition: SET #confcode = FLOOR(RAND()*999999)+111111
The trigger itself gets inserted successfully, but doesn't seem to affect anything..
I guess you want:
SET NEW.confcode = FLOOR(RAND()*999999)+111111;
-- instead of
SET #confcode = FLOOR(RAND()*999999)+111111;
create trigger cal_retweet before insert on T
for each row begin
set NEW.retweet_change = NEW.retweet_count - retweet_count where id_str = NEW.id_str
end
SQL said there is syntax error near "where id_str = NEW.id_str"
My table looks like this. Where id_str is a unique identifier for a specific tweet. Since I am inserting 50 tweets from a single user every minute, there would be many same id_str. What I want to look at is the change of retweet_count every minute. tweeted_at is when the user tweeted, created_at is when this data is inserted into my database. I want to generate retweet_change for each new data inserted into the database compared to the same old tweet (into the column retweet_change). How should I write the trigger?
After reading some of your comments I changed my code to :
create trigger cal_retweet before update on T
for each row
begin
set NEW.retweet_change = NEW.retweet_count - OLD.retweet_count;
end;
There is still syntax error
There are several issues with this trigger.
You have some syntax errors. You need proper semicolons to delimit your statements.
You have a WHERE statement that is out of place (and actually not needed). You are acting on only a single row at a time, you don't have to match on the id_str.
In order to factor in a calculation using an existing value from the row, you need access to the OLD keyword. For that, you need a trigger that happens on UPDATE, not INSERT. On INSERT, the retweet_change is simply the same as retweet_count; you could alter your INSERT statement to fix that problem.
You may need to explicitly add a statement delimiter as per the comments below.
So all together, I think this trigger should look like:
DELIMITER //
CREATE TRIGGER cal_retweet BEFORE UPDATE ON T
FOR EACH ROW
BEGIN
SET NEW.retweet_change = NEW.retweet_count - OLD.retweet_count;
END;//
DELIMITER ;
I've been trying to create a simple BEFORE INSERT trigger on a database table (MySQL v 5.7 ) but I keep receiving a vague "#1064 ... syntax error" message which doesn't help resolve the issue.
Here's the SQL:
CREATE OR REPLACE TRIGGER `CREATE_QUIZ_TRIG` BEFORE INSERT ON `quiz`
FOR EACH ROW BEGIN
SET NEW.ACTIVE = UPPER(NEW.ACTIVE);
SET NEW.CREATED = NOW();
END
/
All I'm trying to do is enforce a column to uppercase and then insert the current date & time into a timestamp column. I've been following the documentation from:
https://dev.mysql.com/doc/refman/5.7/en/trigger-syntax.html
and realise that for multi-statement expression I have to redefine the delimiter at the beginning of the trigger's creation but the same '#1064' error occurs.
This is made even more confusing because when I use phpmyadmin's interface for creating the same trigger it works fine - but won't when I export the generated SQL and try to create the trigger using that!?
Thanks for any help
I didn't realise that, by default, phpmyadmin adds a ; delimiter which was breaking the ; used to end a statement within the BEGIN END block.