SELECT count(*),
DateAdd(second, -DatePart(second, clientTime) ,
DateAdd(ms, -DatePart(ms, clientTime), clientTime))
FROM dbo.V_COMBINED
WHERE (sessionId = '122b')
AND (type = N'sys_goodaction')
AND (paraName = 'value')
GROUP BY DateAdd(second, -DatePart(second, clientTime) % 5
,DateAdd(ms, -DatePart(ms, clientTime), clientTime))