如何在插入触发器mysql之前中断插入查询

Question

How to avoid insert query if some condition get false in Before Insert trigger mysql ?

Here is an example what i want to do:

CREATE DEFINER = CURRENT_USER TRIGGER `mtdb`.`Mytable_BEFORE_INSERT` 
BEFORE INSERT ON `Mytable` FOR EACH ROW
    BEGIN
        IF (NEW.mobile IS NULL OR NEW.mobile = "")
        THEN
            **DO NOT INSERT, RETURN SOME ERROR MESSAGE
        END IF;
    END

Answer 1

There are two ways I can think of

1. Use " Signal " to stop the execution.
2. Change the value of your data such that it violates some constraints, such as setting the primary key to NULL.