Issue
I am trying to sum a tablecolumn on basis of month but I got the following exception:
java.lang.IllegalStateException: Couldn't read row 0, col -1 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it.
the function
public static float test(SQLiteDatabase db) {
String expenditure = MyDatabaseContract.TableExpenditure.ATTR_EXPENDITURE;
String table = MyDatabaseContract.TableExpenditure.TABLE_EXPENDITURE;
String date = MyDatabaseContract.TableExpenditure.ATTR_DATE;
String query = "SELECT SUM(" + expenditure + ") FROM " + table + " WHERE strftime('%m', date)=11";
Cursor cursor = db.rawQuery(query, null);
float total = 0;
if (cursor.moveToFirst())
total = cursor.getInt(cursor.getColumnIndex("Total"));// get final total
return total;
}
the table
public static class TableExpenditure {
public static final String TABLE_EXPENDITURE = "expenditure_table";
public static final String ATTR_PRIMARY_KEY = "pk_expendituretable";
public static final String ATTR_DATE = "date";
public static final String ATTR_CATEGORY = "category";
public static final String ATTR_EXPENDITURE = "expenditure";
public static final String ATTR_COMMENT = "comment";
public static final int N_COLUMNS = 5;
public static final String SQL_CREATE_TABLE =
"CREATE TABLE " + TABLE_EXPENDITURE + "(" + ATTR_PRIMARY_KEY + " INTEGER PRIMARY KEY AUTOINCREMENT," + ATTR_DATE + " DATE," + ATTR_CATEGORY + " TEXT," +
ATTR_EXPENDITURE + " REAL," + ATTR_COMMENT + " TEXT" + ")";
}
In the debugger the cursor contains one item but when calling getInt(..) the app crashes
Solution
The column created for this result:
SUM(" + expenditure + ")
is not called Total
.
Change the sql statement to this:
String query = "SELECT SUM(" + expenditure + ") AS Total FROM " + table + " WHERE strftime('%m', date)=11";
This way you give the name (alias) Total
to the column.
Or since there is only 1 column returned, do this:
total = cursor.getInt(0);
Answered By - forpas
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