Does [My]SQL have a Pre-Processor-like Facility? - sql

Question

I'm writing a small deployment SQL script for my first database-driven app.
In the process, I find that I repeat myself a lot, for instance:
GRANT USAGE ON *.* TO 'foo'#'localhost';
DROP USER 'foo'#'localhost';
CREATE USER 'foo'#'localhost' IDENTIFIED BY 'password';
It would be fantastic if I could use a variable or a macro to replace commonly occurring data. Is it possible to implement something like the the following snippet?
#define USER 'foo' #or "Type USER = 'foo'"
#define HOST 'localhost' #or "Type HOST = 'localhost'"
GRANT USAGE ON *.* TO USER#HOST
DROP USER USER#HOST
CREATE USER USER#HOST IDENTIFIED BY 'password'

Answer 1

Most SQL databases have some kind of bind variables that you can use for that.
For instance, in PostgreSQL you use the \set command in plsql:
\set user = foo
drop user :user;
create user :user identified by 'password';
However, I am not sure if MySQL have something like that. It do have variables, and since the host and user is a string, you might be able to do something like this:
select #user = 'foo';
select #host = 'localhost;
drop user #user##host;
create user #user##host identified by 'password';
If variables doesn't work with the drop and create user statements, you can always modify the mysql.user table directly, just don't forget to execute flush privileges after.
insert into user values(host,#user,PASSWORD('some_pass'),
'Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y');
flush privileges;

Answer 2

You can certainly do something like:
SET #user='foo';