android.database.sqlite.SQLiteException: no such column
For string data type always use quotes like this '"+rid+"'" since rid is String you get error.
You should use +rid only if rid is int.
you need to use apostrophe(') in Where clause checking.. like
db.rawQuery("SELECT _id FROM Meeting where meet='"+rid+"'" , null);
Or, better yet, use a PreparedStatement and bind your variables. It'll escape strings and dates properly for you. It'll also help with SQL injection problems.
You can also use like this.
db.rawQuery("SELECT _id FROM Meeting where meet=?" ,
new String [] {rid});
This will also solve for SQL injection problem.