WEEKS("2002-19-02 ";" 2002-19-02 "; 1) returns 0, because there is not a whole week in between, starting at the first day of the week (monday or sunday, depending on your local settings)
WEEKS ("2002- 19- 02"; "2002- 19- 02"; 1) funtzioak 0 itzultzen du, tartean asteko lehenengo egunean hasten den aste osorik ez dagoelako (astelehena edo igandea, zure ezarpen lokalen arabera)