Can you help me trying to combine multiple triggers into one?

What I have so far throws a: ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ''unit_of_measure'='%') or I have tried adding declares DECLARE val_cal INT(11); DECLARE value CHAR(50); DECLARE unit_of_measure CHAR(1);

Here's what i have:

delimiter $$ CREATE TRIGGER `do_all` BEFORE INSERT ON `telemetry_log` FOR EACH ROW Begin SET new.device_desc = ( select device_desc from id_name_update where device_id=new.device_id ); IF (NEW'.unit_of_measure'='%') THEN SET new.val_cal = ( select hum_cal from id_name_update where device_id=new.device_id); ELSEIF (NEW.'unit_of_measure'='F') SET new.val_cal = ( select temp_cal from id_name_update where device_id=new.device_id); END IF; SET new.value = new.value + new.val_cal; END$$ DELIMITER ;