Chainable filters

resultset.pm

=head3 filter_by_last_issued                                    
                                       
    Koha::Patrons->filter_by_last_issued( { after => DateTime, before => DateTime } );
                                                                     
Returns patrons filtered by whether their last issue falls betwen the passed limits.
                                              
=head4 arguments hashref                                                      
                                      
=over 4                                                  
                                               
=item before (optional) - filter out patrons whose last_issue was since DateTime         
                                                           
=item after (optional) - filter out patrons whose last_issue has been since DateTime      
                                                                             
=back                                                             
                                                           
=cut                                                                       
                                                         
sub filter_by_last_issued {                                                          
    my ( $self, $options ) = @_;
                                                                                             
    return $self                            
      unless ( defined($options)
        && ( $options->{before} || $options->{after} ) );                  
                                                                    
    my $where = {};                                                
    my $attrs = {                                                                      
        join      => 'old_issues',
        '+select' => { max => 'old_issues.timestamp', -as => 'last_issued' },         
        '+as'     => 'last_issued'
    };                                                                    
    my $dtf = Koha::Database->new->schema->storage->datetime_parser; 
                                                                   
    push @{ $attrs->{'having'}->{'-and'} },                         
      { 'last_issued' => { '<' => $dtf->format_datetime( $options->{before} ) }
      }                          
      if $options->{before};                                              
                                                 
    push @{ $attrs->{'having'}->{'-and'} },
      { 'last_issued' => { '>' => $dtf->format_datetime( $options->{after} ) } }
      if $options->{after};                                

    return $self->search( $where, $attrs );           
}

My test script results in the below structure for attrs and where,

$attrs = {
          '+as' => 'last_issued',      
          '+select' => {                                                                                                                                
                         'max' => 'old_issues.timestamp',                                
                         '-as' => 'last_issued'                                  
                       },                                                  
          'having' => {                       
                        '-and' => [
                                    {             
                                      'last_issued' => {
                                                         '<' => '2018-06-28 11:02:47'            
                                                       }                
                                    }                                                       
                                  ]
                      },
          'join' => 'old_issues'
        };

$where = {};

but the final query fails with:

DBD::mysql::st execute failed: Unknown column 'last_issued' in 'having clause' [for Statement "SELECT COUNT( * ) FROM `borrowers` `me` LEFT JOIN `old_issues` `old_issues` ON `old_issues`.`borrowernumber` = `me`.`borrowernumber` WHERE ( ( `me`.`borrowernumber` = ? OR `me`.`borrowernumber` = ? OR `me`.`borrowernumber`
= ? ) ) HAVING `last_issued` < ?" with ParamValues: 0='1560', 1='1561', 2='1562', 3='2018-06-28 11:02:47'] at /usr/share/perl5/DBIx/Class/Storage/DBI.pm line 1836.
No method count found for Koha::Patrons DBIx::Class::Storage::DBI::_dbh_execute(): Unknown column 'last_issued' in 'having clause' at /home/martin/kohaclone/Koha/Objects.pm line 395