solved!
1st friday : (SELECT DATEADD(DAY, DECODE(EXTRACT(DOW FROM START_DATE), 0,5, 1,4, 2,3, 3,2 ,4,1, 6,6, 0), START_DATE) third_friday FROM (SELECT date_trunc('month',current_date) START_DATE))
2nd friday : (SELECT DATEADD(DAY, 7 + DECODE(EXTRACT(DOW FROM START_DATE), 0,5, 1,4,...