Compare difference between two dates using JPA Criteria Query

问题

I am using MySQL as a backend for my application.

I want to execute query below using JPA Criteria Query.

SELECT * 
FROM table1 t1
WHERE datediff(now(), t1.created) >= 20;

Note: Type of created is TIMESTAMP

I want Criteria Query like:

CriteriaBuilder cb = getEntityManager().getCriteriaBuilder();

// select
CriteriaQuery<Table1> query = cb.createQuery(Table1.class);

// from
Root<Table1> root = query.from(Table1.class);

// where
List<Predicate> predicates = new ArrayList<Predicate>();

// TODO: add expression for datediff(now(), t1.created) >= 20

query.where(cb.and(predicates.toArray(new Predicate[0])));

Can any one help?

Thanks in advance.

回答1:

Supposing that created is a java.util.Date, you have to perform the DATEDIFF in java and compare the property with the resulting date:

Calendar c = Calendar.getInstance();
c.add(Calendar.DAY_OF_YEAR, -20);
Date myDate = c.getTime();

predicates.add(cb.lessThanOrEqualTo(root.<Date>get("created"), myDate));

来源：https://stackoverflow.com/questions/24669544/compare-difference-between-two-dates-using-jpa-criteria-query