SQL Fiddle
sqlfiddle.com
sqlfiddle.com
It's a neat concept, but it needs serious polishing before I'd consider going to this even for quick and dirty testing or demo purposes.
/newb
...and then I remembered I'm an idiot.
BTW - I basically built this site to facilitate answering SQL questions on Stack Overflow. Here's my SO profile: http://stackoverflow.com/users/808921/jake-feasel
MSSQL: The EXECUTE permission was denied on the object 'xp_cmdshell', database 'mssqlsystemresource', schema 'sys'.: exec xp_cmdshell
MySQL: Access denied for user 'user_46783'@'localhost' (using password: YES): load data infile '/etc/passwd' into table leet;
Doesn't require a startup of the database - the results can be discarded and you don't have to worry about cleaning it up :)
Generally, just a fast way to test things - I would see it coming in handy during some presentations maybe?
I'd use this tool.
An idea: Integrate with different ORMs (Python SQLAlchemy, Ruby ActiveRecord etc.) and let users execute code against the schemas.
Would obviously require a sandboxed execution environment, like some of the pastebins that allow code execution (for instance http://codepad.org).
http://ondras.zarovi.cz/sql/demo/?keyword=default
these two projects should merge...