MySQL 8.0

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create table if not exists table1
(puuid varchar(50) not null unique);

create table if not exists table2
(puuid varchar(50) not null unique);
create table if not exists table3
(puuid varchar(50) not null unique)

create trigger temp_trigger
before INSERT
on table2  for each ROW 
BEGIN 
    declare c int;
    select count(*) into c from table1 t1 where t1.puuid = NEW.puuid;
    if (c > 0) THEN 
    -- abort insert because puuid cannot be null
    set NEW.puuid = NULL;
    end if;
    
END;
insert into table1 (puuid)
values ('22');

insert into table2 (puuid)
values ('22')
Column 'puuid' cannot be null

create trigger temp_trigger2
before INSERT
on table3  for each ROW 
BEGIN 
    declare c int;
    select count(*) into c from table1 t1 where t1.puuid = NEW.puuid;
    if (c > 0) THEN 
        SIGNAL SQLSTATE '45000'
			SET MESSAGE_TEXT = 'id already exists';
    end if;
    
END;
insert into table3 (puuid)
values ('22')
id already exists

SELECT * FROM table1;


puuid


22


SELECT * FROM table2;
SELECT * FROM table3;