hql CASE语句从查询中排除数据

Question

I have this query in hql:

SELECT d.code as row1, d.name as row2, d.contractor.name as row3, 
        case when e is null then 'no emission'
            else case when e.zone is null then 'no coverage' 
                else e.zone.name 
            end
        end
FROM Design d
    left join d.emissions e
WHERE (d.code =:codeParam or :codeParam = null)
    and (d.contractor =:contracParam or :contracParam = null)

I want this to list every Design even if it doesn't have an Emission or the Emission it has doesn't have a zone. If I only do:

case when e is null then 'no emission'
     else 'emission'
end

Every Design is listed correctly, but when I add the second case-when it only lists the Designs with zone.

What am I doing wrong? Please tell me if you need more information. Any help will be highly appreciated

Answer 1

You should follow the structure:

case
   when ... then
   when ... then
   else ...
end

Read more in docs .