MySQL 8.0

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CREATE TABLE game ( id INT AUTO_INCREMENT PRIMARY KEY,
                    name VARCHAR(255));

SHOW CREATE TABLE game;

INSERT INTO game VALUES
(1, 'Starcraft'),
(2, 'Broodwar'),
(3, 'Broodwar:Resurrection');


Table
Create Table


game
CREATE TABLE `game` (
  `id` int NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci


CREATE TRIGGER DuplicateGameName_update
BEFORE UPDATE ON game
FOR EACH ROW
BEGIN
  IF (EXISTS(SELECT 1 FROM game WHERE name = NEW.name AND id <> NEW.id)) THEN
    SIGNAL SQLSTATE VALUE '45000' SET MESSAGE_TEXT = ' Такая игра уже имеется в базе!';
  END IF;
END
SELECT * FROM game;


id
name


1
Starcraft

2
Broodwar

3
Broodwar:Resurrection


UPDATE game SET name = 'FarCry' WHERE id = 1;
SELECT * FROM game;


id
name


1
FarCry

2
Broodwar

3
Broodwar:Resurrection


UPDATE game SET name = 'Broodwar:Resurrection' WHERE id = 2;
 Такая игра уже имеется в базе!

SELECT * FROM game;


id
name


1
FarCry

2
Broodwar

3
Broodwar:Resurrection