@@ -, +, @@ 
 selections
---
 .../prog/en/modules/reports/guided_reports_start.tt   | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)
--- a/koha-tmpl/intranet-tmpl/prog/en/modules/reports/guided_reports_start.tt	
+++ a/koha-tmpl/intranet-tmpl/prog/en/modules/reports/guided_reports_start.tt	
@@ -882,7 +882,7 @@ 
                                                 <label for="sql_params_[% sql_param.labelid | html %]">[% sql_param.entry | html %]:</label>
                                                 [% IF (sql_param.select_multiple) %]
                                                     <select name="[%- sql_param.input.name | html -%]" tabindex="1"  id="[%- sql_param.input.id | html -%]" multiple>
-                                                        <option value="null" hidden></option>
+                                                        <option value="%" hidden></option>
                                                 [% ELSE %]
                                                     <select name="[%- sql_param.input.name | html -%]" tabindex="1"  id="[%- sql_param.input.id | html -%]">
                                                 [% END %]
@@ -1581,8 +1581,13 @@ 
 
             $('#report_param_form').on('submit', function(e) {
                 $('#report_param_form').find('select[multiple]').each( function (i) {
-                    var $selected = $('option:first', this).val();
-                    $(this).val($selected);
+                    if( $(this).find('option:selected').length === 0 ) {
+                        $(this).val(['%']);
+                    }
+                    else if( $(this).find('option:selected').length > 1 ) {                    
+                        var $selected = $('option:first', this).val();
+                        $(this).val($selected);
+                    }  
                 });
             });
         }
--