If you are testing MySQL queries output from Joomla! then you may need to replace the #_ prefix on the table name with the prefix in use on your site.
For help using MySQL the manual is available on line but is not the most simple and straightforward document :-( There are some better starter tutorials at W3Schools and many other places if you search with Google.
To help Debug MySQL queries in ChronoForms you will find that some are output when you add a DeBugger action to your form event; you can also temporarily turn on Site Debug which will show a long list of queries generated in creating the page. Using the Test View icon to see your form without the template will remove many of these.