Finding out largest tables on MySQL Server

mysql> SELECT CONCAT(table_schema, '.', table_name),

    ->        CONCAT(ROUND(table_rows / 1000000, 2), 'M')                                    rows,

    ->        CONCAT(ROUND(data_length / ( 1024 * 1024 * 1024 ), 2), 'G')                    DATA,

    ->        CONCAT(ROUND(index_length / ( 1024 * 1024 * 1024 ), 2), 'G')                   idx,

    ->        CONCAT(ROUND(( data_length + index_length ) / ( 1024 * 1024 * 1024 ), 2), 'G') total_size,

    ->        ROUND(index_length / data_length, 2)                                           idxfrac

    -> FROM   information_schema.TABLES

    -> ORDER  BY data_length + index_length DESC

    -> LIMIT  10;

taken from: http://www.mysqlperformanceblog.com/2008/02/04/finding-out-largest-tables-on-mysql-server/