SQL Statement - Week of Month

用以計算某個日期是當月的第幾週
date1為要計算的日期

[In SQL Server]
CONVERT(CHAR(1), DATEPART(WK, DATE1) - DATEPART(WK,DATEADD(DD,-DAY(DATE1),DATE1)+1)+1)

 [In DB2]
WEEK(DATE1) - WEEK(DATE1 - DAY(DATE1) DAY + 1 DAY) + 1