How to get the Last Day of the Given Date Data.

I am taking the Data Like below

Country Date_DB Sales Date_DB2
A     12-12                 200        12-2012 B     10-15                300        10-2015

C     02-12                20        02-2012

We are expecting like Below

Country    Sales   DB_Date_DB      LDM

A              200       12-12                31-Dec-2012
 

Procedure:

1) First Convert the Given Date Related column into exact Date like using below calculation.

(This Calculation for Date_DB, it means Date is Like 10-12)

date( "01" +  "/" +  str(left([Date DB],2))  +"/" +( "20" + str(right([Date DB],2))))

2) Use the below Calculation to Last day of the Given Date.

datepart( 'day', dateadd('day', -1, dateadd('month', 1,[Converttodate_MM-YY])))

3) Expected Output.

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If data is available like 12-2012 then use the below calculation to Convert into Date.

date( "01" +  "/" +  str(left([Date DB2],2))  +"/" +  str(right([Date DB2],4)))