how to get particular id field null in Sqlite in android

public void onCreate(SQLiteDatabase db) {
    db.execSQL("CREATE TABLE " + INFR_TABLE
            + "(_id INTEGER PRIMARY KEY NOT NULL," + CATEGORY + " integer,"
            + STATUS + " text, " + FEEDBACK + " text, " + VISITDETAILID + " text,  "
            + IMAGE + " BLOB)");

this is my table i want when i pass table id then it should return CATEGORY contains null value if Feedback,image or VISITDETAILID if any field is null i have 10 rows :

public String ChekcWhichRowisNull(String id)
{

    cursor = db.query(INFR_TABLE, ID, "folder_name is null or folder_name = ?", new String[] {""}, null, null, CATEGORY + " DESC");
    return CATEGORY.toString();

}

i have to create function so that it should check if i will pass id then it will check all Column of that row and it will return category this has null value how to wrong funcation but unable to get out put please help