can i specify a db name in a var?

sneakyimp

I've written a pretty lengthy migration script to move data from an old database format to a new one. I have since learned that the database names that I've written into my sql may not be the database names on d-day when we actually perform the migration.

I was wondering if it's possible to set a db name in a variable and have all of the subsequent queries refer to that variable as a db name. I tried this but it doesn't work:

SET @current_db_name='mbamdev_new';
SELECT * FROM @current_db_name.admin;

I get an error

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '@current_db_name.admin' at line 1

bradgrafelman

By "script" do you mean PHP script? If so, why not just use PHP variables instead of SQL variables?

sneakyimp

No, it's just SQL. Sorry if that was ambiguous.

dagon

looks like a no to me:

User variables are intended to provide data values. They cannot be used directly in an SQL statement as an identifier or as part of an identifier, such as in contexts where a table or database name is expected, or as a reserved word such as SELECT. This is true even if the variable is quoted, as shown in the following example:

http://dev.mysql.com/doc/refman/5.0/en/user-variables.html

sneakyimp

Thanks Dagon.

So the var approach obviously fails. Is there some way to accomplish the same thing using an alias or something?