Question

I’m trying to make a query where I get data from two tables but it won’t show me any result. I know there is a result because in SQLite3 it displays at least one, e.g.

sqlite> select eventthemename, eventtypename from event_type, event_theme
   ...> where event_type.eventthemes = event_theme._id     
   ...> and event_type._id = '2';
Tribal | Dance

I’m using a content provider. Does anyone have an idea on how to make this?

Answer 1

Your question isn’t really clear (you should include some of your code!), so I might not answer your question as you hoped. But following is a simple example I have where I join two tables in one query:

private static final String QUERY_ALL_COURSES_WITH_SEMESTER =
 "SELECT * FROM Course JOIN Semester ON semesterId = courseSemesterId";

public Course getCourseByCodeAndSemester(String courseCode, Semester semester)
{
 Course result = null;
 String whereClause = " WHERE courseCode = '" + courseCode.toUpperCase() + "'"
   + " AND semesterId = " + semester.getInternalId();
 Cursor cursor = db.rawQuery(QUERY_ALL_COURSES_WITH_SEMESTER + whereClause, null);
 if (cursor.moveToFirst())
 {
  result = Course.createFromCursor(cursor);
 }
 cursor.close();
 return result;
}

Note that there are probably many things that could be optimized in this function, but it illustrates how it can be done.