querydsl transformer group by count

java sql querydsl

Wouter Willems · Nov 3, 2014 · Viewed 17k times · Source

I am stuck trying to get a query (QueryDSL) to work that gives me a count of distinct categories. For example, what I am trying to achieve:

categoryA -> 10 entries
categoryB -> 20 entries

This is what i have so far:

query().from(application)
            .transform(groupBy(application.category).as(list(application)));

However, this gives me for each category a list of all whole entries, I just want to get a count of this.

I tried messing around with count() but no luck.

Anybody know how to do this?

Answer

Note that as of Querydsl 4.x, the accepted answer by Timo Westkämper is no longer valid. Breaking changes in Querydsl 4.0 have removed the query.list() method.

A solution working with Querydsl 4.0+ would now be:

query.from(application)
     .groupBy(application.category)
     .select(application.category, application.category.count())
     .fetch();