How does one concatenate database values into a string?

I would like to string together database values into a string. Something like $a "text" $b. And then use the entire string as a variable, let's say $c.

Is it bette开发者_JS百科r to do this at the database level? Will php use lots of resources to do this?

Depends on the database, in mysql you can use the function CONCAT

For example, UPDATE users SET NAME=CONCAT('asd', 'asdfac') WHERE id=2;

perfectly acceptable - calculated or derived field in mysql for example

 select
  c.firstname,
  c.lastname,
  concat(c.firstname, ' ', c.lastname) as fullname
 from
  customer c
 where
  c.cust_id = 1;

No, either database or php won't notice this operation.
Better to do in php as it would be a lot readable.