How to create a trigger in the concatenation of auto_increment value column and a column that has a default value

DELIMITER $$
CREATE DEFINER=`root`@`localhost` TRIGGER `grade_one_BINS`
 BEFORE INSERT ON `grade_one` FOR EACH ROW
set new.student_no = concat(new.letter, ' - ',new.num)

      

there is a problem with the concatenation of a num column that has an auto-increment value as the trigger is before the insert, because it will show the value 0, since auto-increment is still 0 until you enter some values ​​... can you help me ?? ?

+3


source to share


1 answer


I suggest you don't store the data again in another column that you already have in columns num

and letter

.

You can generate a column student_no

on the fly in your chosen



select *,
       concat(letter, ' - ', num) as student_no
from your_table

      

+1


source







All Articles