Steps to reproduce the issue

Create a SqlField form item with an error - e.g mistype column name

Expected result

Sensible error message

Actual result

Vague 'An error has occurred.' error message

System information (as much as possible)

Additional comments

Changing SqlField.php line 293 to include something like this would help:

'
try
{
$items = $db->loadObjectList();
}
catch (ExecutionFailureException $e)
{
Factory::getApplication()->enqueueMessage(Text::_('JERROR_AN_ERROR_HAS_OCCURRED'), 'error');
Factory::getApplication()->enqueueMessage($e->getMessage(), 'error');
Factory::getApplication()->enqueueMessage($this->query->__toString(), 'error');
}'