(:
   file:    check_ipedsVars_freq.xq
   date:    10-June-2010
   author:  Gary Lewis
   purpose: Returns a frequency distribution showing the number of variables by the
            number of years they are represented in the IPEDS directory data files.
   use:     Run program from its path location.
   example: zorba -f -q check_ipedsVars_freq.xq -z indent=yes
:)

<results>
{
let $tmp :=
   for $i in fn:doc("../xml/metadata/ipedsVars.xml")/variables/var
   let $name := $i/@name,
       $year := $i/@year
   group by
       $name
   return <var name="{$name}" years="{count($year)}" />
return
   let $tmp2 :=
      for $j in $tmp
      let $name := $j/@name,
          $years := $j/@years
      group by
          $years
      return <freq years="{$years}" numVars="{count($name)}" />
   return 
      for $k in $tmp2
      order by xs:integer($k/@years)
      return $k
}
</results>