if (in_array("your_table_name", $sql['tables'])) {
    var_dump($statement);
    print_r($statement);
}

http://wiki.typo3.org/User:Layne_obserdia/Extbase

You can debug the EXTBASE-SQL-Querys by inserting the debug-Code into the File "typo3\sysext\extbase\Classes\Persistence\Storage\Typo3DbBackend.php".
Search for the Method "buildQuery". That is where the querys are build. Insert your code and see the result.
For Example, add the lines before the return-Statement.
Change *your_table_name* to your table name. This will prevent you from dumping every Query. You just will see the querys for the specified table.

Debug extbase-SQL-Querys

PHP