--- loncom/interface/loncoursedata.pm	2004/07/06 15:50:03	1.137
+++ loncom/interface/loncoursedata.pm	2004/07/22 15:55:57	1.138
@@ -1,6 +1,6 @@
 # The LearningOnline Network with CAPA
 #
-# $Id: loncoursedata.pm,v 1.137 2004/07/06 15:50:03 matthew Exp $
+# $Id: loncoursedata.pm,v 1.138 2004/07/22 15:55:57 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -2303,6 +2303,14 @@ sub get_sum_of_scores {
     if (! defined($courseid)) {
         $courseid = $ENV{'request.course.id'};
     }
+    if (defined($students) && 
+        ((@$students == 0) ||
+         (@$students == 1 && (! defined($students->[0]) || 
+                              $students->[0] eq ''))
+         )
+        ){
+        undef($students);
+    }
     #
     &setup_table_names($courseid);
     my $dbh = &Apache::lonmysql::get_dbh();
@@ -2325,7 +2333,9 @@ sub get_sum_of_scores {
     $sth->execute();
     my $rows = $sth->fetchrow_arrayref();
     if ($dbh->err) {
-        &Apache::lonnet::logthis('error = '.$dbh->errstr());
+        &Apache::lonnet::logthis('error 1 = '.$dbh->errstr());
+        &Apache::lonnet::logthis('prepared then executed, fetchrow_arrayrefed'.
+                                 $/.$request);
         return (undef,undef);
     }
     return ($rows->[0],$rows->[1]);
@@ -2505,7 +2515,8 @@ sub get_student_data {
     my $sth = $dbh->prepare($request);
     $sth->execute();
     if ($dbh->err) {
-        &Apache::lonnet::logthis('error = '.$dbh->errstr());
+        &Apache::lonnet::logthis('error 2 = '.$dbh->errstr());
+        &Apache::lonnet::logthis('prepared then executed '.$/.$request);
         return undef;
     }
     my $dataset = $sth->fetchall_arrayref();
@@ -2574,7 +2585,8 @@ sub get_response_data {
     my $sth = $dbh->prepare($request);
     $sth->execute();
     if ($dbh->err) {
-        &Apache::lonnet::logthis('error = '.$dbh->errstr());
+        &Apache::lonnet::logthis('error 3 = '.$dbh->errstr());
+        &Apache::lonnet::logthis('prepared then executed '.$/.$request);
         return undef;
     }
     my $dataset = $sth->fetchall_arrayref();
@@ -2630,7 +2642,8 @@ sub get_response_data_by_student {
     my $sth = $dbh->prepare($request);
     $sth->execute();
     if ($dbh->err) {
-        &Apache::lonnet::logthis('error = '.$dbh->errstr());
+        &Apache::lonnet::logthis('error 4 = '.$dbh->errstr());
+        &Apache::lonnet::logthis('prepared then executed '.$/.$request);
         return undef;
     }
     my $dataset = $sth->fetchall_arrayref();
@@ -2682,7 +2695,8 @@ sub get_response_time_data {
     my $sth = $dbh->prepare($request);
     $sth->execute();
     if ($dbh->err) {
-        &Apache::lonnet::logthis('error = '.$dbh->errstr());
+        &Apache::lonnet::logthis('error 5 = '.$dbh->errstr());
+        &Apache::lonnet::logthis('prepared then executed '.$/.$request);
         return undef;
     }
     my $dataset = $sth->fetchall_arrayref();
@@ -2772,7 +2786,8 @@ sub get_student_scores {
     my $sth = $dbh->prepare($request);
     $sth->execute();
     if ($dbh->err) {
-        &Apache::lonnet::logthis('error = '.$dbh->errstr());
+        &Apache::lonnet::logthis('error 6 = '.$dbh->errstr());
+        &Apache::lonnet::logthis('prepared then executed '.$/.$request);
         return undef;
     }
     $request = 'SELECT score,COUNT(*) FROM '.$tmptable.' GROUP BY score';
@@ -2780,7 +2795,8 @@ sub get_student_scores {
     $sth = $dbh->prepare($request);
     $sth->execute();
     if ($dbh->err) {
-        &Apache::lonnet::logthis('error = '.$dbh->errstr());
+        &Apache::lonnet::logthis('error 7 = '.$dbh->errstr());
+        &Apache::lonnet::logthis('prepared then executed '.$/.$request);
         return undef;
     }
     my $dataset = $sth->fetchall_arrayref();