declare @InputDate datetime
set @InputDate = GetDate()
select dateadd(mm,datediff(mm,0,@InputDate)+ 1,0)-1 as last_day_of_month

-Omni

public string GetNumberOfDays(DateTime strStartDate,DateTime strEndDate)
{
//Start Date
string fStartDate = strStartDate.ToString();
string fEndDate = strEndDate.ToString();
string[] SD1=fStartDate.Split(” “.ToCharArray());
string[] ED1 = fEndDate.Split(” “.ToCharArray());
fStartDate =SD1[0].ToString();
fEndDate =ED1[0].ToString();
string[] StartDateArray = fStartDate.Split(”/”.ToCharArray());
string[] EndDateArray = fEndDate.Split(”/”.ToCharArray());
Int16 SDate =Convert.ToInt16(StartDateArray[1]);
Int16 SMonth = Convert.ToInt16(StartDateArray[0]);
Int16 SYear = Convert.ToInt16(StartDateArray[2]);
//End Date
Int16 EDate = Convert.ToInt16(EndDateArray[1]);
Int16 EMonth = Convert.ToInt16(EndDateArray[0]);
Int16 EYear = Convert.ToInt16(EndDateArray[2]);
Int16 TotalDay = 0;
string strTDays=”";
Int16 NumDayInMonth =Convert.ToInt16(DateTime.DaysInMonth(SYear, SMonth));
if (SYear<=EYear)
{
if (SMonth <= EMonth)
{

while (SDate !=EDate && SMonth!=EMonth)
{
if (SDate != NumDayInMonth)
{
SDate = Convert.ToInt16(SDate+1) ;
TotalDay =Convert.ToInt16( TotalDay+1);
}
if (SDate == NumDayInMonth)
{
SDate = 1;
SDate =Convert.ToInt16(SDate+1);
SMonth =Convert.ToInt16(SMonth+1);
TotalDay = Convert.ToInt16(TotalDay+1);
}

}
strTDays =Convert.ToString(TotalDay+1);

}
}
return strTDays;
}