MariaDB [db1]> DELETE FROM tab1 WHERE col1='abcd';

ERROR 1366 (22007): Incorrect decimal value: 'abcd' for column 'col1' at row 1

CREATE TABLE tab1 (

    col1 char(10) NOT NULL

);

CREATE TABLE tab1_tgr (

    col1 decimal(8,0) NOT NULL

);

DELIMITER //

CREATE TRIGGER delete_tab1_tgr BEFORE DELETE ON tab1 FOR EACH ROW

BEGIN

    INSERT INTO tab1_tgr (col1) VALUES (old.col1);

END //

DELIMITER ;

INSERT INTO tab1 VALUES ('abcd');

DELETE FROM tab1 WHERE col1='abcd';