Query From SQLite DataBase Android - cursor

Question

I am trying to make a query from sqlite database by passing a value. Based on the passed value I need to fetch a unique record if data is available.Below is my code so far I have written
public String getDataOnlytransid(String Questionid)
{
String [] columns=new String[] {TRANS_ID};
Cursor c=ourDatabse.query(DATABASE_TABLE, columns, null,null,TRANS_ID,TRANS_ID + "=?", Questionid,null);
String result="";
int iRowID=c.getColumnIndex(TRANS_ID);
for(c.moveToFirst();!c.isAfterLast();c.moveToNext())
{
result=result + c.getString(iRowID); // n is for newline
}
c.close();
return result;
}
Then I am calling above method using below code
final question_savelistDB db = new question_savelistDB(context);
db.open();
final String question_id=db.getDataOnlytransid(dataList.get(position).getSaved_qid());
db.close();
But it is giving below error.What is the wrong I am doing
android.database.sqlite.SQLiteException: 1st ORDER BY term out of range - should be between 1 and 1 (code 1): , while compiling: SELECT trans_id FROM PaymentTable GROUP BY trans_id HAVING trans_id=? ORDER BY 2

Answer 1

The 7th argument of the method query() is the ORDER BY clause of the statement (without the ORDER BY keywords) and it should be a string.
Instead, you pass Questionid which is an integer and the ORDER BY clause becomes:
ORDER BY 2
You must pass the string TRANS_ID, which is the name of the one and only column that your query returns:
Cursor c = ourDatabse.query(DATABASE_TABLE, columns, null, null, TRANS_ID, TRANS_ID + "=?", TRANS_ID, null);
But, if the column TRANS_ID is unique in the table, you don't need the ORDER BY clause at all, since you expect 1 row at most in the results, so there is no need to sort and you could just pass null.
Also, you don't need the GROUP BY clause which is the 5th argument and instead of passing the parameter Questionid to a HAVING clause you should use the WHERE clause:
Cursor c = ourDatabse.query(DATABASE_TABLE, columns, TRANS_ID + "=?", TRANS_ID, null, null, , null, null);
Also, there is no need for a loop after you get the cursor.
You should only check if there is a row in the cursor and get the value of its only column:
public String getDataOnlytransid(String Questionid) {
String [] columns=new String[] {TRANS_ID};
Cursor c = ourDatabse.query(DATABASE_TABLE, columns, TRANS_ID + "=?", TRANS_ID, null, null, , null, null);
String result="";
if (c.moveToFirst()) result = c.getString(0);
c.close();
return result;
}
Also, you pass the parameter named Questionid for a column named TRANS_ID. Are you sure this is correct?
If it is, then I assume that you do it because you want to check if that Questionid exists in the table.
But you should know that getDataOnlytransid(), as it is, it returns the same value as Questionid if it exists in the table.