jugbugs

I am having some trouble with forming a nested SQL query to grab the first pass yield of a given widget. This is more of an intellectual fulfillment requirement vs it having to be done this way. My table is: create table data (sn varchar(64),an varchar(64), tracking timestamp, result boolean); Where sn is the serial number, an is the assembly number (model), tracking is the time the entry was inserted and result is pass or fail (0 or 1 respectively). The table can contain multiple entries for a given serial number (like if a widget failed three times then passed one). I want to count the number of passes and fails per assembly number but only include the first time a given sn was seen (min(tracking)/distinct sn). I was able to accomplish this using temporary tables, but would like to do single nested statement instead. Thanks in advance for the help.