#!perl
use strict;
use DBI;
use SQL::Abstract::More;
my $sqla = SQL::Abstract::More->new();
my $case = q!
  CASE
    WHEN record.is_public = 'Yes' THEN 'public'
    WHEN EXISTS ( SELECT 1
      FROM permissions
      WHERE permissions.rec_id = record.id AND user_id = ? )
      THEN 'accessible'
  ELSE
    'private'
  END 
  as viewable!;

my ($sql,undef) = $sqla->select(
  -columns => [$case,'record.id','record.display_name'],
  -from    => 'record',
  -where   => { 'record.id' => 1 }
);
print $sql;