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hibernatecounttraversal

Count sub-subelements with hql

i want to get Elements and the amount of certain sub-subelements without actually loading them, i tried this:

f, count(f.themen.responses) FROM Forum f WHERE f.grouping=:group

but i get 

node to traverse cannot be null!

how can i archieve something like that?

tanks

Solution

  • You get node to traverse cannot be null!, because you didn't specified SELECT in query. Next problem is that aggregate function (COUNT) is used in query, but f is not in GROUP BY.

    Query where both of those problems are fixed is:

    SELECT f, count(f.themen.responses) 
FROM Forum f WHERE f.grouping=:group
GROUP BY f