As I am working my SQL, for example if I have
select
concat(author_fname, ' ', author_lname)..
....
from...
The question that I have is when I do multiple queries, I have to type that concat command over and over again.
Is there a way that I can set a global variable let's say
set
@full_name =(
select
concat(author_fname, ' ',
author_lname)
from
books
);
Now I only need to do:
select full_name
from books;
But my set command does not work, I don't think declare is the way to go, is there a way to tackle this problem? Thank you so much!
You can use a view:
create view v_books as
select concat(author_fname, ' ', author_lname) as full_name, b.*
from books b;
You will see the column if you select from the view.
Or use a generated column if you want it when selecting directly from the table:
alter table books add full_name varchar(255) generated always as
(concat(author_fname, ' ', author_lname));
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.