Example

$database =& JFactory::getDBO();

$prefix = $database->_table_prefix;
$tables = array( $prefix.'content_frontpage', $prefix.'content_rating' );
$result = $database->getTableFields( $tables );
print_r( $result );

Result

Array
(
    [jos_content_frontpage] => Array
        (
            [content_id] => int
            [ordering] => int
        )
 
    [jos_content_rating] => Array
        (
            [content_id] => int
            [rating_sum] => int unsigned
            [rating_count] => int unsigned
            [lastip] => varchar
        )
 
)