title: Calculate Quarter Start Date
body: <p>As I have to calculate Start date of specific quarter and Quarter No from any financial year start date based on @firstMonthOfFiscalyear parameter. Let's say if @firstMonthOfFiscalyear =4 mean my financial year start date is 1 April and my quarter no start as below.
  Q1 - April to Jun
  Q2 - July to Sep
  Q3 - Oct to Dec
  Q4 - Jan to March</p>
  
  <p>This quarter no will change based on @firstMonthOfFiscalyear parameter value.</p>
  
  <p>From this I am able to get Quarter number but not able to get Start date of that quarter. So anyone can help me on this.</p>
  
  <pre><code>DECLARE @StartDateTime DATETIME
  DECLARE @EndDateTime DATETIME
  DECLARE @firstMonthOfFiscalyear int = 4     --Finanical year start month
  SET @StartDateTime = '2017-04-01'
  SET @EndDateTime = '2019-03-31';
  WITH DateRange(Dates) AS 
  (
  SELECT @StartDateTime as Date
  Union ALL
  SELECT DATEADD(d,1,Dates)
  FROM DateRange 
  WHERE Dates &lt; @EndDateTime
  )
  SELECT Dates
  ,FLOOR(((12 + MONTH(Dates) - @firstMonthOfFiscalyear) % 12) / 3 ) + 1   as quarterNo
      , DATEADD(month, (IIF((month(dates)-@firstMonthOfFiscalyear)&lt;0,(month(dates)-@firstMonthOfFiscalyear)+12,(month(dates)-@firstMonthOfFiscalyear))/3)*3,  CAST( DATEFROMPARTS(year(dates),@firstMonthOfFiscalyear ,1) as Datetime)) as QuarterStartDate
  FROM DateRange
  OPTION (MAXRECURSION 0)
  </code></pre>