Best SQL Crime Ever

Given a table like this:

mysql> select * from delta;
+------------+-------+
| end_time   | level |
+------------+-------+
| 1245937320 |     5 | 
| 1245937565 |     1 | 
| 1245954231 |     5 | 
| 1245954844 |     2 | 
| 1245956014 |     4 | 
| 1245963214 |     5 |

Doing this:

select u from ( select @ac:=0 i, NULL u union select * from ( select 0,
concat('http://chart.apis.google.com/chart?cht=pc&chd=t:',
group_concat(100*(q/@ac)),'&chl=',group_concat(l
separator '|'),'&chs=300x200') u from ( select q, l, @ac:=(@ac + q) from (
select sum(d)q, l from( select @s:=((select min(end_time) from delta)) d,
(select min(end_time) from delta) st, 0 l union select (end_time-@s) d,
(@s:=(end_time)), level from delta order by st)x group by l having (l is not
null and l > 0)) e ) r) m) pp order by u desc limit 1

Gives you this:

http://chart.apis.google.com/chart?cht=pc&chd=
t:0.3070,2.9300,2.5503,94.2127&chl=1|2|4|5&chs=300x200

Which is this:

Or rather, it’s a pie chart of how much time was spent at each level.

MySQL variables are fun, dangerous, and messy.