querydsl - list condition

Question

that's my code :

final JPAQuery query = new JPAQuery(entityManager);
final List<Tuple> myList = query
                .from(QPerson.person)
                    .groupBy(QPerson.person.name)
                    .where(myBooleanExpression) //myBooleanExpression declared at the top of code              
                    .list(QPerson.person.name, 
                          QPerson.person.cash.sum());

What i want to do is to list :

• name (without condition)
• sum(cash) ONLY IF (condition), ELSE (..)

Any suggestion on how to do it?

Answer 1

You can use an SQL CASE in your case, like:

final JPAQuery query = new JPAQuery(entityManager);
final List<Tuple> myList = query
    .from(QPerson.person)
    .groupBy(QPerson.person.name)
    .where(myBooleanExpression)
    .list(QPerson.person.name, 
          new CaseBuilder()
              .when(yourOtherBooleanExpression).then(QPerson.person.cash.sum())
              .otherwise(yourOtherNumericExpressionOrLiteral));

• yourOtherBooleanExpression should be a Predicate (like BooleanExpression)
• yourOtherNumericExpressionOrLiteral should be a NumberExpression<T> or T itself, where T is the base type of QPerson.person.cash.