Question

I am new in Android Application Development
I use the UNION query like that

public Cursor getAll() {
        return (getReadableDatabase()
                .rawQuery(
                        "SELECT _id,x,y from Not where _id="
                                + id
                                + " UNION ALL " + "SELECT _id,z,q from Q_A where z="
                                + zid, null));
    }

    public String getX(Cursor c) {
        return (c.getString(1));
    }

    public String getY(Cursor c) {
        return (c.getString(2));
    }
    public String getQ(Cursor c) {
        return (c.getString(3));
    }

it will give the error

IllegalStateException: get field slot from row 0 col 3 failed

I am totally Stuck on this and get confused whether my query is wrong or my accessing methods is wrong ?

Answer 1

You are going in the wrong way.
This is a simple solution with the join query by two tables

SELECT a._id, a.x, a.y, b._id, b.z, b.q 
FROM Not a, Q_A b 
WHERE a._id = id 
AND b.z = zid
a.comId = b.refId