Trigger doesn't get created, despite no errors being detected - mysql

Table:
create table produto
(
referencia varchar(3) primary key,
descricao varchar(50) unique,
estoque int not null default 0,
preco_normal decimal(10,2),
preco_desconto decimal(10,2)
);
Trigger (I tried creating it without a delimiter to no avail as well):
delimiter //
create trigger desconto before insert
on produto
for each row
begin
if new.estoque < 5 then
set new.preco_desconto = new.preco_normal * 0.90;
else
set new.preco_desconto = new.preco_normal;
end if;
end//
delimiter ;
The trigger result:
But when I use drop trigger if exists desconto;
The output says Trigger does not exist
Any ideas on how to solve this?

Related

MySQL Non Sequential ID

Challenge:
Create a method to set "auto_increment" values for tables in a non-sequential way.
The goal is to override the "auto_increment" mechanism and allow the function "LAST_INSERT_ID()" to continue working as expected (returning an INT), so that no changes are needed in software side.
My Solution
The method I found is based on an auxiliary table (unique_id), that stores values available to be assigned. Values are then selected randomly, and removed from the tables as used. When the table gets empty, a new set of ID's is created.
This example is working as expected, but with one problem.
Tables for the demo:
CREATE TABLE `unique_id` (
`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`id`)
)
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB
AUTO_INCREMENT=100;
CREATE TABLE `test_unique_id` (
`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
`name` VARCHAR(50) NOT NULL DEFAULT '0',
PRIMARY KEY (`id`)
)
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB
AUTO_INCREMENT=1;
Defined a stored procedure and a function:
DELIMITER $$
DROP PROCEDURE IF EXISTS `UNIQUE_ID_REFILL`$$
CREATE PROCEDURE UNIQUE_ID_REFILL()
BEGIN
DECLARE a INT Default 0 ;
simple_loop: LOOP
SET a=a+1;
INSERT INTO unique_id (id) values(null);
IF a=100 THEN
LEAVE simple_loop;
END IF;
END LOOP simple_loop;
END $$
DROP FUNCTION IF EXISTS `UNIQUE_ID_GET`$$
CREATE FUNCTION UNIQUE_ID_GET()
RETURNS INT(11)
MODIFIES SQL DATA
BEGIN
DECLARE new_id INT(11);
DECLARE unique_id_count INT(11);
SET new_id = 0;
SELECT COUNT(*) INTO unique_id_count FROM unique_id;
IF unique_id_count=0 THEN
CALL UNIQUE_ID_REFILL();
END IF;
SELECT id INTO new_id FROM unique_id ORDER BY RAND() LIMIT 1;
DELETE FROM unique_id WHERE id = new_id;
RETURN new_id;
END $$
Created a Trigger on the destination table (test_unique_id):
CREATE TRIGGER test_unique_id__unique_id BEFORE INSERT ON test_unique_id
FOR EACH ROW
SET NEW.id = UNIQUE_ID_GET();
The solution is getting the random ID's as expected:
INSERT INTO test_unique_id(name) VALUES ('A'),('B'),('C');
Creates the rows:
id name
154 'A'
129 'B'
173 'C'
The Problem
The main problem is that LAST_INSERT_ID() stops working... and the software side is broken:
SELECT LAST_INSERT_ID();
0
Any ideas on how to solve this problem? or any other different approach to the challenge?
Thank you very much.

How to insert multiple records from one table into another on update of third table in MySQL

I'm having difficulty with developing the logic in MySQL. I don't know how to INSERT multiple records from a Table AFTER UPDATE.
CREATE TABLE primeira(
ID int PRIMARY KEY AUTO_INCREMENT,
nome varchar(30) NOT NULL,
valor int DEFAULT 0
);
CREATE TABLE segunda(
ID int PRIMARY KEY AUTO_INCREMENT,
ID_primeira int,
ultimo_valor int DEFAULT 0,
credito int NOT NULL,
limite int DEFAULT 0,
FOREIGN KEY(ID_primeira) references primeira(ID)
);
CREATE TABLE terceira(
ID int PRIMARY KEY AUTO_INCREMENT,
ID_segunda int,
`data` TIMESTAMP DEFAULT CURRENT_TIMESTAMP NOT NULL,
estado boolean DEFAULT false,
FOREIGN KEY(ID_segunda) references segunda(ID)
);
CREATE TRIGGER tr_segundaLimite_INS
BEFORE INSERT ON segunda FOR EACH ROW
SET NEW.limite = New.ultimo_valor + New.credito;
DELIMITER //
CREATE TRIGGER tr_primeira_UPD
AFTER UPDATE ON primeira FOR EACH ROW
IF (SELECT limite FROM segunda WHERE segunda.ID_primeira = New.ID AND
(limite - NEW.valor)< 50) THEN
INSERT INTO terceira(ID_segunda)
VALUES ((SELECT ID FROM segunda WHERE segunda.ID_primeira = New.ID
AND (limite - NEW.valor)< 50));
END IF;
END
//
DELIMITER ;
I'm going to use procedures with functions to SELECT the data. The problem with this TRIGGER is that it's not working when there are multiple matching records.
The error that I am getting is-
subquery returns more than 1 row.
The objective is: After an update of the primeira.valor, the trigger would subtract segunda.limite - New.valor. If this difference is < 50 then all the matching segunda.ID would be registered at terceira.ID_segunda on terceira table.
I'm using data below:
INSERT INTO primeira(nome,valor)
VALUES
('Burro',800),
('Chiconizio',300),
('Xerosque',400),
('Shrek',600);
INSERT INTO segunda(ID_primeira,ultimo_valor,credito)
VALUES
(1,600,800),
(1,700,400),
(1,800,500),
(2,150,200),
(2,200,180),
(2,250,300);
UPDATE primeira
SET Valor = 330
WHERE ID = 2;
You need CURSOR for this. You can try the following trigger code. I hope this will fix your issue.
DELIMITER //
CREATE TRIGGER tr_primeira_UPD
AFTER UPDATE ON primeira FOR EACH ROW
BEGIN
DECLARE v_limite_diff INT;
DECLARE v_seg_id INT;
DECLARE done INT DEFAULT FALSE;
DECLARE c1 CURSOR FOR SELECT (s.limite - NEW.valor), s.id
FROM segunda s WHERE s.ID_primeira = New.ID;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
OPEN c1;
my_loop: LOOP
FETCH c1 INTO v_limite_diff, v_seg_id;
IF done THEN
LEAVE my_loop;
END IF;
IF( v_limite_diff < 50 ) THEN
INSERT INTO terceira(ID_segunda) VALUES(v_seg_id);
END IF;
END LOOP;
END//
DELIMITER ;

Need help writing the case statement - MySQL Cursor

I created two columns in student table for my database. I now need to create a cursor for the student table. I need to make use of the input parameters for start and end student Id’s to filter the results in the cursor query.
I also need to open the cursor created and check if the student has an email assigned or not. If the email is not assigned I need to update the email column to have an email assigned to the student.
Finally to why I want help:
I cannot figure out how I would write the case statements for this cursor. I have tried to think of a good way to do this and not succeeded. Please help!!
DELIMITER $
DROP PROCEDURE IF EXISTS CURSOR_DEMO$
CREATE PROCEDURE CURSOR_DEMO(start_student_id INT
,end_student_id INT
)
BEGIN
DECLARE l_table_name VARCHAR(50);
DECLARE iam_done INT DEFAULT 0;
DECLARE l_sql_stmt VARCHAR(5000);
SET #l_sql_stmt='ALTER TABLE STUDENT ADD EMAIL VARCHAR';
SELECT #l_sql_stmt;
prepare stmt from #l_sql_stmt;
execute stmt;
SET #l_sql_stmt='ALTER TABLE STUDENT ADD PHONE int(10)';
SELECT #l_sql_stmt;
prepare stmt from #l_sql_stmt;
execute stmt;
DECLARE TBL_CUR CURSOR FOR
SELECT EMAIL FROM STUDENT.TABLES WHERE TABLE_SCHEMA='MYSQLDB';
BEGIN
DECLARE CONTINUE HANDLER FOR NOT FOUND SET IAM_DONE=1;
OPEN TBL_CUR;
tbl_loop:LOOP
FETCH tbl_cur INTO l_table_name;
IF IAM_DONE = 1 THEN
LEAVE tbl_loop;
END IF;
CASE WHEN l_table_name = 'STUDENT' THEN
ELSE BEGIN END;
END CASE;
END LOOP tbl_loop;
CLOSE TBL_CUR;
END;
END$
DELIMITER ;
Is this the kind of thing you need?
/*
drop table student;
delimiter $$
CREATE TABLE `student` (
`id` int(11) NOT NULL ,
`name` char(1) NOT NULL,
`email` varchar(1),
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8$$
drop table email;
delimiter $$
CREATE TABLE `email` (
`id` int(11) NOT NULL ,
`type` varchar(8) NOT NULL,
`person_id` int,
`email` varchar(1),
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8$$
;
*/
DELIMITER $
DROP PROCEDURE IF EXISTS CURSOR_DEMO$
CREATE PROCEDURE CURSOR_DEMO(start_student_id INT
,end_student_id INT)
BEGIN
declare email_person_id int;
declare email_address varchar(50);
DECLARE done INT DEFAULT 0;
DECLARE CUR CURSOR FOR
SELECT person_id,email FROM sandbox.email where type = 'student';
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;
OPEN CUR;
cur_loop:LOOP
IF done = 1 THEN
LEAVE cur_loop;
END IF;
FETCH CUR INTO email_person_id,email_address;
update student
set email = email_address
where id = email_person_id
and email is null
;
END LOOP cur_loop;
CLOSE CUR;
commit;
END$
DELIMITER ;
truncate table student;
insert into student
values
(1,'A','1'),
(2,'B','1'),
(3,'C',null),
(4,'D',null),
(5,'E',null),
(6,'G',null),
(7,'F',null)
;
truncate table email;
insert into email
values
(1,'student',1,'a'),
(2,'student',2,'b'),
(3,'faculty',7,'z'),
(4,'student',3,'c')
;
select * from student;
call cursor_demo(1,10);
select * from student;

MySQL Trigger Insert Before Not Firing

I'm trying to add a trigger for auditing to initialize a datetime field on an insert. Does anyone see what might be causing this trigger to not fire???
USE example;
CREATE TABLE USERS (
ID INT UNSIGNED NOT NULL AUTO_INCREMENT,
FULLNAME VARCHAR(128) NOT NULL,
`PASSWORD` CHAR(88) NOT NULL,
EMAIL VARCHAR(128) NOT NULL,
FLAGS TINYINT UNSIGNED DEFAULT 0,
CREATED DATETIME,
UPDATED TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
UNIQUE INDEX(EMAIL),
PRIMARY KEY( ID )
);
DELIMITER $$;
CREATE TRIGGER USER_T BEFORE INSERT ON USERS FOR EACH ROW
BEGIN
SET NEW.CREATED = CURRENT_TIMESTAMP();
END;$$
DELIMITER ;
INSERT INTO USERS(FULLNAME, `PASSWORD`, EMAIL) VALUES('Admin', 'sQnzu7wkTrgkQZF+0G1hi5AI3Qmzvv0bXgc5THBqi7mAsdd4Xll27ASbRt9fEyavWi6m0QP9B8lThf+rDKy8hg==', 'root#localhost');
It looks like you are using the ; as a delimiter here
SET NEW.CREATED = CURRENT_TIMESTAMP();
END;$$
DELIMITER ;
Try this:
DELIMITER $$;
CREATE TRIGGER USER_T BEFORE INSERT ON USERS FOR EACH ROW
BEGIN
SET NEW.CREATED = CURRENT_TIMESTAMP();
END $$
DELIMITER ;

Split string procedure can't find table

I am trying to get this procedure to work and it is stumping me. I simply want this procedure to populate a temp table with the separated values from a table of CSV values.
DELIMITER $$
DROP PROCEDURE IF EXISTS String_Split $$
CREATE PROCEDURE String_Split
(
vString VARCHAR(255),
vSeparator VARCHAR(5)
)
BEGIN
DECLARE vDone tinyint(1) DEFAULT 1;
DECLARE vIndex INT DEFAULT 1;
DECLARE vSubString VARCHAR(15);
DROP TABLE IF EXISTS tmpValues;
CREATE TEMPORARY TABLE tmpValues (tmpVal VARCHAR(255));
WHILE vDone > 0 DO
SET vSubString = SUBSTRING(vString, vIndex,
IF(LOCATE(vSeparator, vString, vIndex) > 0,
LOCATE(vSeparator, vString, vIndex) - vIndex,
LENGTH(vString)
));
IF LENGTH(vSubString) > 0 THEN
SET vIndex = vIndex + LENGTH(vSubString) + 1;
INSERT INTO tmpValues VALUES (vSubString);
ELSE
SET vDone = 0;
END IF;
END WHILE;
END; $$
I call on it:
CALL String_Split(my_csv.keywords, ',');
And I get this:
Error Code: 1109. Unknown table 'my_csv' in field list
I'm not getting this because the table is there and the appropriate database is selected.
CREATE TABLE `my_csv` (
`id` int(10) NOT NULL AUTO_INCREMENT,
`keywords` text NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 $$
INSERT INTO `my_csv` () VALUES
(1, 'featured, 3/8, Diamond, Engagement Ring, 14K, White Gold, Gold'),
(2, '1/3, Diamond, Engagement Ring, 14K, White Gold, Gold'),
(3, 'featured') $$
Instead of calling the table name and field in the call function, you need to get the value first, then call the procedure. Here's a working example.
SELECT #keyword :=keywords from my_csv;
CALL String_Split(#keyword, ',');
Edit:
That only grabbed the last row. This one selects all of them. Also, doing this the vSeparator variable in the procedure was too small, so I bumped that up to 255.
SELECT #keyword :=group_concat(keywords) FROM my_csv;
CALL String_Split(#keyword, ',');
select * from tmpValues;