What's Wrong with My SQL Query?
While we're on the subject of debugging, the system debug mode in Joomla is very handy when troubleshooting SQL database queries. If a SQL query is at all complex, I usually test it outside of Joomla (for example, using phpMyAdmin) before incorporating its coding in PHP. Even so, when I code a query inside Joomla, it often doesn't work correctly the first time.
With system debugging enabled (Global Configuration > System), at the bottom of the page is a display of all the SQL queries that were run to create that page, as shown in Figure 6.
Figure 6 System debug display of SQL queries.
If a SQL query doesn't work correctly, you can copy-and-paste it into your SQL tool (such as phpMyAdmin) and troubleshoot the query there. After you find the error, you can go back and make the necessary PHP code changes.