大家好，我在SQL中遇到了这个问题：mysql在第4行总是给我语法错误，但我真的不知道这可能是什么

Question

这里是代码：

CREATE TRIGGER inserisci_richiesta_noID AFTER INSERT ON Richiesta
FOR EACH ROW
BEGIN    
    IF (NEW.ID_Cliente == NULL AND (NEW.Email NOT IN (SELECT Email FROM Utente))) THEN
        INSERT INTO Utente(ID, Nome, Cognome, Email, Telefono, ID_Livello_accesso)
        VALUES (NULL, 'Generato', 'Automaticamnete', NEW.Email, NEW.Telefono, 1);
        UPDATE Richiesta
        SET ID_Cliente = (SELECT ID FROM Cliente WHERE Email = :NEW.Email);
    ELSE NEW.ID_Cliente == NULL AND NEW.Email IN (SELECT Email FROM Utente;) THEN
        UPDATE Richiesta
        SET ID_Cliente = (SELECT ID FROM Cliente WHERE Email = NEW.Email);
    END IF;
END;

它给我这个错误：

1064-您的SQL语法有误；检查与您的MySQL服务器版本相对应的手册，以在'== NULL AND（NEW.Email NOT IN（SELECT Email From Utente））附近使用正确的语法在第4行插入U'

Answer 1

DELIMITER $$

在Richiesta上插入后创建inserisci_richiesta_noID触发器每行开始如果（NEW.ID_Cliente为NULL和（NEW.Email NOT IN（从Utente选择电子邮件）））然后插入Utente（ID，Nome，Cognome，电子邮件，Telefono，ID_Livello_accesso）值（NULL，'Generato'，'Automaticamnete'，NEW.Email，NEW.Telefono，1）更新RichiestaSET ID_Cliente =（从Cliente WHERE电子邮件中选择的ID = NEW.Email）；ELSE IF（NEW.ID_Cliente为NULL和NEW.Email IN（从Utente选择电子邮件））然后更新RichiestaSET ID_Cliente =（从Cliente WHERE电子邮件中选择的ID = NEW.Email）；万一;END $$