make sure cursor is initialized correctly before accessing data from it

Question

Can anyone help me how to execute this query?

I am trying to fetch distinct supervisor from project table. supervisor is column name and its index is 5.

try {

String query = "select distinct supervisor from project ";
            Cursor cursor= db.rawQuery(query,null);//query( query , null, null,null,null,null,null);

            if (cursor.moveToFirst()) {
                do {
                    labels.add(cursor.getString(5));
                } while (cursor.moveToNext());
            }

           // finish();
           cursor.close();
           db.close();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return labels;
    }

Project is name of table and supervisor is column name.. I want all distinct supervisor but I am getting error... can you please help me to execute this distinct query ? — Faheem Imtiaz, Aug 30 '17 at 17:16

Bhuvanesh BS · Accepted Answer · 2017-08-30T17:41:34.887

0

Your query is wrong.

You have to query write like this.

select * from project where YOUR_CONDITION

I don't know what you exactly trying to do.

Example query.

select * from customers where LastName = 'Tremblay'

To get Distinct value of supervisor you should query like this.

select * from project group by supervisor

Hope it helps:)

edited Aug 30 '17 at 17:41

answered Aug 30 '17 at 17:02

Bhuvanesh BS

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then just try `select * from project` – Bhuvanesh BS Aug 30 '17 at 17:07
select * from project is working fine but i need only distinct names from database one name is repeating many times – Faheem Imtiaz Aug 30 '17 at 17:10
we can't execute distinct query without condition ? – Faheem Imtiaz Aug 30 '17 at 17:18
Simple, use `select distinct supervisor from project` – Bhuvanesh BS Aug 30 '17 at 17:18
its not working i am trying this .. getting error "make sure cursor is initialized correctly before accessing data from it " – Faheem Imtiaz Aug 30 '17 at 17:21
https://stackoverflow.com/questions/25884095/how-can-i-delete-duplicates-in-sqlite this will help you to delete duplicate from database – Bhuvanesh BS Aug 30 '17 at 17:28
Mark it as correct answer if it works for you. It will help others. – Bhuvanesh BS Aug 31 '17 at 14:12

score -1 · Answer 2 · answered Aug 30 '17 at 17:03

-1

You could use an if statement ie if cursor != null, do something.

answered Aug 30 '17 at 17:03

Joshua

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make sure cursor is initialized correctly before accessing data from it

2 Answers2