title: crystal report error: "a string is required here" on select
body: <p>I run the following code in crystal reports and it tells me that </p>
  
  <blockquote>
    <p>" string is required here"</p>
  </blockquote>
  
  <p>on the second case.  I've tried casting {?Pm-Student_course_attendance_csv.Level} as a string, but no luck</p>
  
  <pre><code> Global NumberVar grade;
   Global NumberVar baseline;
  
  Select ({?Pm-Student_course_attendance_csv.Level})
    Case "R", "TL", "TU", "OTH", "P", "BTECFS": 
      If (CStr({PM_csv.mv_value}) = "Pass") Then
         "On Track"
      Else
         "Below"
  
    Case "H", "ASD", "AD", "AS", "G":     //error from this line onwards inclusive
       Select (CStr({PM_csv.mv_value}))
          Case "A*":
              grade := 11
          Case "A*/A":
              grade := 10
          Case "A":
              grade := 9
          Case "A/B":
              grade := 8
          Case "B":
              grade := 7
          Case "B/C":
              grade := 6
          Case "C":
              grade := 5
          Case "C/D":
              grade := 4
          Case "D":
              grade := 3
          Case "D/E":
              grade := 2
          Case "E":
              grade := 1
          Case "U":
              grade := 0
          Default :
              grade := 0;
  </code></pre>