Webmaster Forum / ColdFusion / Advanced Techniques / March 2007

No, I believe the OP is asking to find out how many times the date range
 9/1/?? to 6/30/?? occurs between the dates of 1/1/2007 and 9/40/2009.

To clarify the entire first date range must be contained inside of the
second, correct.  You don't care about partial overlaps and the
beginning or the end?

The years in the 9/1 to 6/30 range is irrelevant, I think. They can be any
year. What I'm looking for is how many sets of September 1 through June 30
occur in a larger date range like January 1, 2007 and September 30, 2009.  In
this example there is a partial set at 1/1/2007 through 6/30/2007. Two full
sets between 9/1/2007 and 6/30/2008 and 9/1/2008 through 6/30/2009. Finally
there is a partial set 9/1/2009 through 9/30/2009. I hope that explains what
I'm trying to do.

You want to count months in each set and normalize it to a fraction of 9
months.  A full set would normalize to 1.0, a partial set with 3 months would
normalize to 0.3.  The attached code should give you an idea of how to approach
this problem.

<CFSET set = ArrayNew(2)>
<CFSET set[1][1] = "9/1/2007">
<CFSET set[1][2] = "6/30/2008">
<CFSET set[2][1] = "12/1/2007">
<CFSET set[2][2] = "5/30/2008">

<CFSET count = 0>
<CFLOOP INDEX="i" FROM="1" TO="2">
    <CFSET count = count + DateDiff("m", set[i][1], set[i][2]) / 9>
</CFLOOP>

<CFOUTPUT>#NumberFormat(count, "999.9")#</CFOUTPUT>

Yet another method...

<cfset start_date = DateFormat('01/01/2007', 'mm/dd/yyyy')>
<cfset end_date = DateFormat('09/30/2009', 'mm/dd/yyyy')>
<cfset start_year = DatePart('yyyy', start_date)>
<cfset end_year = DatePart('yyyy', end_date)>
<cfset schoolyear_start = '09/01/'>
<cfset schoolyear_end = '06/30/'>

<cfset count = 0>
<cfloop index="rec" from="#start_year#" to="#end_year#">
    <cfset tmp_start = DateFormat('#schoolyear_start##rec#', 'mm/dd/yyyy')>
    <cfset tmp_end = DateFormat('#schoolyear_end##rec + 1#', 'mm/dd/yyyy')>
    <cfif DateCompare(tmp_start,start_date) gt -1 and DateCompare(tmp_end,
end_date) eq -1>
        <cfset count = count + 1>
    </cfif>
</cfloop>

<cfoutput>
<br>There are #count# school year periods between #start_date# and #end_date#
</cfoutput>