Error "1241 - Operand should contain 1 column" in Trigger that checks duplicities

Question

I’m doing this Rigger to check if it already exists dados_id and referente_obs in the bank table

But returns this error:

1241 - Operand should contain 1 column(s);

BEGIN
    IF (NEW.id_dados and NEW.referente_obs) not in (
        select A.id_dados,A.referente_obs
        From banco as A  
        where (NEW.id_dados = A.id_dados and NEW.referente_obs = A.referente_obs)
    ) THEN
       CALL `Insert Not Allowed.`;

    END IF;
END

Answer 1

You cannot make a nested SELECT with two columns. You must separate it into two SELECT: one for A.id_data and one for A.re. It’s like this:

IF (NEW.id_dados and NEW.referente_obs) not in (
            select A.id_dados, A.referente_obs
            From banco as A  
            where (NEW.id_dados = A.id_dados and NEW.referente_obs = A.referente_obs)
)

Try it like this:

IF (NEW.id_dados NOT IN 
(
  SELECT A.id_dados
  FROM banco AS A  
  WHERE NEW.id_dados = A.id_dados
)) AND ((NEW.referente_obs) NOT IN
(
  SELECT A.referente_obs
  FROM banco AS A  
  WHERE NEW.referente_obs = A.referente_obs
))

Answer 2

BEFORE INSERT ON banco FOR EACH ROW BEGIN IF (NEW.id_dados, NEW.referente_obs) not in ( ( select A.id_dados From banco as A where NEW.id_dados = A.id_dados ), ( select A.referente_obs From banco as A where NEW.referente_obs = A.referente_obs )) THEN CALL Insert Not Allowed.; END IF; END