How to calculate Week Start Date and Week End date using DAY_DT in Obiee 11g

In OBIEE 11g, many times we have to calculate on the fly, the various dates functions like Week_Start_date, Week_End_Date, Previous_Yr_Date etc,  just using the Date column. Few projects have Date Dimensions not properly structured to have all columns. So here we have the logical sql’s to calculate the same:
We can calculate the week start date using the below sql:
TIMESTAMPADD(SQL_TSI_DAY,- DAYOFWEEK(MIN(“Dim – Date”.” Date Column”)) + 1, MIN(“Dim – Date”.” Date Column”))
For Week End Date, use the below Sql:
TIMESTAMPADD(SQL_TSI_DAY, 7-DAYOFWEEK(MAX(“Dim – Date”.” Date Column”)), MAX(“Dim – Date”.”Date Column”))
DAYOFWEEK returns an integer in the range of 1 to 7. A value of 1 represents the Monday.
Courtesy: Google