Doing sum's if certain conditions are true

[Ian Barnes]

Hi,

I am trying to build a query that does a sum if a certain parameter is set.
For example:

I have a row with four fields: code1, code2, duration and bytes. My current
query looks something like this: SELECT code1 as code, sum(bytes) as bin,
max(bytes) as min, avg(bytes) as ain, count(bytes) as cin, sum(duration) as
dur from data group by code; which returns something like this:

+---------------------------+--------------+-----------+-------------+----------+-------------+
| code                      | bin          | min       | ain         |
cin      | dur         |
+---------------------------+--------------+-----------+-------------+----------+-------------+
| NONE                      | 103939170759 | 485089817 |   3739.1827 |
27797297 | 11681839027 |

Now, what i need todo is exclude certain info from the above NONE entry if
code2 is equal to something. So for example (in php terminology):

if(code == 'NONE') {
 if(code2 == 'DENIED') { continue; }
 else {
     bin += bytes;
     if(bytes > min) { min = bytes; }
     cin++;
     dur += dur;
 }
}

after that i could work out the average by dividing bin / cin for what in
the report is called ain. Is there any way of achieving this via the sql
query because the above is a hugely tedious way of doing it. I know mysql
has an if() statement, but I have no idea how to implement it using what i
want to achieve above.

Thanks in advance.
Ian