I am trying to find out how to do a simple table join on my two tables using a sqlite database in an android application.
Is the simplest way to use CursorJoiner or is there any easier way?
To query data from multiple tables, you use INNER JOIN clause. The INNER JOIN clause combines columns from correlated tables. Suppose you have two tables: A and B. A has a1, a2, and f columns.
The OUTER JOIN Though SQL standard defines three types of OUTER JOINs: LEFT, RIGHT, and FULL, SQLite only supports the LEFT OUTER JOIN.
In the implementation of SQLiteDatabase and SQLiteQueryBuilder you will see that it is possible to pass the tables you want to join to the table
argument of query
even though the documentation implies it will only take a single name of a table. The documentation for SQLiteQueryBuilder is more clear and even suggests things like foo, bar
or foo LEFT OUTER JOIN bar ON (foo.id = bar.foo_id)
.
If you're willing to use a third-party library, I recommend using Active Android
https://github.com/pardom/ActiveAndroid
using it you can merge tables like this
From query = new Select() .from(Foo.class) .innerJoin(Bar.class) .on("Foo.Id=Bar.Id");
you can even get a cursor back to use in loaders
Cursor cursor = Cache.openDatabase().rawQuery(query.toSql(), query.getArguments());
more details here
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