MySQL 5.7

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CREATE TABLE `users` (
  `id` bigint unsigned NOT NULL AUTO_INCREMENT,
  `email` varchar(255) NOT NULL,
  `username` varchar(255) NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `idx-users-email` (`email`)
);
INSERT INTO users (email, username) VALUES 
("pioz@example.org", "pioz"),
("luke@example.org", "luke"),
("mike@example.org", "mike");
SELECT * FROM users;


id
email
username


1
pioz@example.org
pioz

2
luke@example.org
luke

3
mike@example.org
mike


INSERT INTO users (email, username) VALUES 
('luke@example.org', 'luke2'),
('mike@example.org', 'mike2') 
ON DUPLICATE KEY UPDATE username=VALUES(username);

SELECT * FROM users;


id
email
username


1
pioz@example.org
pioz

2
luke@example.org
luke2

3
mike@example.org
mike2


CREATE PROCEDURE add_update_user(IN e_mail VARCHAR(25), IN user_name VARCHAR(25) )
BEGIN
    DECLARE maxB4 INT DEFAULT 0;
    DECLARE current INT DEFAULT 0;
    
    SELECT MAX(ID) INTO maxB4 FROM users;
    INSERT INTO users (email, username) VALUES 
       (e_mail, user_name) 
       ON DUPLICATE KEY UPDATE username=VALUES(username);
      
    SELECT ID INTO current FROM users WHERE email =e_mail;
    SELECT CASE WHEN maxB4 < current THEN CONCAT('New user with ID ', current, ' created')
      ELSE CONCAT('User with ID ', current, ' updated') END Report;
      /*SELECT CASE WHEn maxB4 < current THEN 1 ELSE 0 END;*/
END
call add_update_user('jake@example.com','Jake');


Report


New user with ID 6 created


call add_update_user('jake@example.com','Jason');


Report


User with ID 6 updated

id	email	username
1	pioz@example.org	pioz
2	luke@example.org	luke
3	mike@example.org	mike