Mash

SELECT COUNT(*)
FROM (SELECT DISTINCT sourceIP, destIP FROM Alerts WHERE Alerts.name='W32_sasser_worm_a' OR Alerts.name='ServiceName' OR Alerts.name='Port_Num' OR Alerts.name='sasser_transfer_upexe');

SELECT MIN(Count) FROM (
SELECT COUNT(*) as Count FROM Alerts WHERE sourceIP='218.104.83.171' AND destIP='140.115.82.108' AND name='W32_sasser_worm_a'
UNION ALL SELECT COUNT(*) as Count FROM Alerts WHERE sourceIP='218.104.83.171' AND destIP='140.115.82.108' AND name='ServiceName'
UNION ALL SELECT COUNT(*) as Count FROM Alerts WHERE sourceIP='218.104.83.171' AND destIP='140.115.82.108' AND name='Port_Num'
UNION ALL SELECT COUNT(*) as Count FROM Alerts WHERE sourceIP='218.104.83.171' AND destIP='140.115.82.108' AND name='sasser_transfer_upexe'
);