Many out there will have different ideas about this, some using procs, some using a function, others using a shell script. Well I didn’t want to spend much time on it so decided a group_concat(concat would be enough.
There is no genius, rather laziness :) but what if you have a hundred databases and you want to drop them all?

mysql Thu Mar  3 13:50:06 2011 > pager sed 's/,/ /g'
PAGER set to 'sed 's/,/ /g''
mysql Thu Mar  3 13:50:32 2011 > select group_concat(concat('drop database ',SCHEMA_NAME,';')) from information_schema.schemata where SCHEMA_NAME !='mysql' and SCHEMA_NAME !='information_schema';
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| group_concat(concat('drop database ' SCHEMA_NAME ';')) …