Q. How to find total days in a month using sql server

DECLARE @Month INT=2, @Year INT=2018, @FirstDate DATE,@LastDate DATE, @TotalDays INT

SET @LastDate=(SELECT DATEADD(DAY,-1,DATEADD(MONTH,@Month,DATEADD(YEAR,@Year-1900,0))))

SET @FirstDate=(SELECT DATEADD(MONTH,@Month-1,DATEADD(YEAR,@Year-1900,0)))

SET @TotalDays=(DATEDIFF(D,@FirstDate,@LastDate))+1

SELECT @FirstDate [First Date of Month] ,@LastDate [Last Date of Month], @TotalDays [Total Days in Month]

out put will be