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Language:
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Language:
English
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7.14. Tips & Tricks
To order a result by the size of a collection, use the following query:
select usr.id, usr.name from User as usr left join usr.messages as msg group by usr.id, usr.name order by count(msg)
If your database supports subselects, you can place a condition upon selection size in the where clause of your query:
from User usr where size(usr.messages) >= 1
If your database doesn't support subselects, use the following query:
select usr.id, usr.name from User usr.name join usr.messages msg group by usr.id, usr.name having count(msg) >= 1
As this solution can't return a
User
with zero messages because of the inner join, the following form is also useful:
select usr.id, usr.name from User as usr left join usr.messages as msg group by usr.id, usr.name having count(msg) = 0