Convert a SQL query in Java Persistence Query Language (JPQL) - sql

Question

I'm having a little problem to convert this SQL query to JPQL:
select max(datePurchase) from purchases where userId = id and date_trunc('day',datePurchase)
in (select distinct (date_trunc('day',datePurchase)) as day from purchases where userId = id and datePurchase < initialDate and datePurchase > finalDate) group by date_trunc('day',datePurchase)
This sql is working well, that returns de last purchase per day made from a user. I tried to do the same, in JPQL:
Query query = em.createQuery("SELECT u MAX(u.datePurchase) FROM Purchases u WHERE u.userId.id = :id AND FUNC('day',u.datePurchase)" +
"IN (SELECT DISTINCT (FUNC('day',u.datePurchase)) AS day FROM Purchases WHERE u.userId.id = :id AND u.datePurchase < :finalDate AND u.datePurchase > :inicialDate) GROUP BY FUNC('day',u.datePurchase)");
query.setParameter("id", idUsuario);
query.setParameter("dataInicial", dataInicial);
query.setParameter("dataFinal", dataFinal);
List<MovSaldo> saldos = (List<MovSaldo>) query.getResultList();
em.getTransaction().commit();
The errors are:
"The IN expression does not have a valid expression." "An identification variable must be provided for a range variable declaration."
Probably is not something very difficult, but i have already spent a little frustrating time in it. Can someone please help me?

Answer 1

Although the answer is probably late for you I still posted it because it might help someone in the future.
In the nested select you have to put an identifier for the entity you are working with: FROM Purchases p and update things like (FUNC('day',u.datePurchase)) to (FUNC('day',p.datePurchase))
Best!