>i mean there several day eg. 10.11.2004,09.09.2004,13.11.2004,06.10.2004 which date to be equal in these days between min date 09.09.2004 and max date 13.11.2004 ?
>
>TIA
Is this what you want?

m.ldmindate = min(date1,date2,date3,date4)
m.ldmaxdate = max(date1,date2,date3,date4)
m.ldavgdate = m.ldmindate + int((m.ldmaxdate - m.ldmindate)/2)