Question

How can I build a query in ORMLite so that I can use the orderBy function (using either the one with the raw string or the parametrized one) referencing an attribute of a different entity than the one of the dao I’m building the query from? My query is built like that:

// Inner query for performances
QueryBuilder<Performance, String> performancesQB = performanceDao.queryBuilder();
performancesQB.selectColumns("performance_id");
SelectArg performanceSelectArg = new SelectArg();
performancesQB.where().lt("date", performanceSelectArg);

// Outer query for Order objects, where the id matches in the performance_id
// from the inner query
QueryBuilder<Order, String> ordersQB = orderDao.queryBuilder();
ordersQB.where().isNull("user_id").and().in("performance_id", performancesQB);
ordersQB.orderByRaw("performances.date DESC");
pastOrdersQuery = ordersQB.prepare();

And the exception I’m getting whenever I try to execute this query is:

android.database.sqlite.SQLiteException: no such column: performances.date:,
   while compiling: SELECT * FROM `orders` WHERE
     (`user_id` IS NULL AND `performance_id` IN
     (SELECT `performance_id` FROM `performances` WHERE `date` < ? ) )
     ORDER BY performances.date DESC 

The only solution I see here is writing a raw query myself using a JOIN instead of a nested select. May this be a good solution?

Answer 1

ORMLite now supports simple JOIN queries. Here the docs on the subject:

http://ormlite.com/docs/join-queries

So your query would now look something like:

QueryBuilder<Performance, String> performancesQB = performanceDao.queryBuilder();
SelectArg performanceSelectArg = new SelectArg();
performancesQB.where().lt("date", performanceSelectArg);
performancesQB.orderBy("date", false);

// query for Order objects, where the id matches
QueryBuilder<Order, String> ordersQB = orderDao.queryBuilder();
ordersQB.join(performancesQB).where().isNull("user_id");
pastOrdersQuery = ordersQB.prepare();