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I have a sqlite database in android , for example :

Table 1 person:

  • column 1: id
  • column 2: name
  • column 3: friends

Table 2 friends:

  • column 1: id
  • column 2: allFriends

the id is the same in both tables, id in table1 == id in table2 i want to get all the values from table2 in specific column "allFriends" by the id and insert all the String values from the column into String array / arrayList.

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1  
Seems very simple, so what have you tried? – Roope Jul 25 '16 at 8:51
up vote 1 down vote accepted

Try this,

  public ArrayList<String> getAllFriends(int id) {
    ArrayList<String> friendsNames = new ArrayList<>();
    SQLiteDatabase sqLiteDatabase = null;
    try {
        String query = "select * from person P join friends F on F.id = P.id where P.id = " + id;
        Cursor cursor = sqLiteDatabase.rawQuery(query, null);
        while (cursor.moveToNext()) {
            friendsNames.add(cursor.getString(cursor.getColumnIndex("allFriends")));
        }
    }catch(Exception ex){
        Log.e(TAG,"Erro in geting friends "+ex.toString());
    }
    return friendsNames;
  }
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what is the person P and friends F ? – Daniel Levi Jul 25 '16 at 9:04
    
Its an Aliases. Read more from w3schools.com/sql/sql_alias.asp – Pramod Waghmare Jul 25 '16 at 9:05
    
SELECT * should be always avoided. Use field lists instead. – Rotwang Jul 25 '16 at 9:25
up vote 0 down vote

Your SQL query:

SELECT allFriends FROM friends where id == Id_from_person

Id_from_person - id of person who friends you want to recieve from DB.
For executing query read this.

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Ofc. It is not copy-paste answer. You need to figure out a little bit by yourself to solve your question. – Stanislav Parkhomenko Jul 25 '16 at 8:53

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