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javaandroidsqliteandroid-sqlite

How to retrieve Real type data from specific cell in android sqlite?

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In this table, I want to retrieve the value 55.2 in a variable. This value is at row 5 (ID=5) and in the column 'Weight' of type REAL.

I can already get the desired row number which is stored in 'lastID' and I know that my data is in the column 'Weight'. So I have my X and my Y in the table.

I also know the sqlite command to retrieve the 55.2 in my cursor:

Cursor cursor2 = db.rawQuery("SELECT Weight FROM <MYTABLE> WHERE ID=" + lastID, null);
Double lastWeight = cursor2.getDouble(0);  //This line is wrong, I need the help here!

But I can't get the 55.2 value I am looking for in my variable lastWeight from cursor2.

Any idea?

Addendum

Here the create table:

String CREATE_TABLE2 = "CREATE TABLE " + <MYTABLE> + " (" + UID2 + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                COL_2 + " TEXT," + COL_3 + " TEXT," + COL_4 + " REAL," + COL_5 + " REAL);";
db.execSQL(CREATE_TABLE2);
Solution

  • After the execution of this line:

    Cursor cursor2 = db.rawQuery("SELECT Weight FROM <MYTABLE> WHERE ID=" + lastID, null);

    you get the results in cursor2.
    A Cursor instance like cursor2 is used to loop through its rows and to do so you must first place its index at the 1st row by moveToFirst():

    if (cursor2.moveToFirst()) {
    Double lastWeight = cursor2.getDouble(0);
    ........................................
}

    The if statement is necessary just in case the cursor does not contain any rows.