Question

我在SQLite表中有大约30条记录，其中10条记录属于来自在线的来源，其余20条记录属于来自的来源离线

现在，我想从records获取属于来源的所有Online，因为我写了这个：

String sQuery = "SELECT * FROM " + TABLE_REMINDERS + " where " + KEY_SOURCE + " = 'Online'";

但是通过使用上述查询，我获取数据库中的所有记录，无论它属于脱机还是在线

所以我错了，为什么我无法获取属于源的数据＆＃39; Online＆＃39;仅

然而，我在delete data的表中使用以下查询source 'Online'并且它对我有效：

db.execSQL("delete from "+ TABLE_REMINDERS + " where " + KEY_SOURCE + " = 'Online'");

代码

public List<Reminder> getAllOnlineReminders(){

        // String selectQuery = "SELECT * FROM " + TABLE_REMINDERS + " where " + KEY_SOURCE + " = 'Online'";

        String[] args = new String[]{"Online"};

        List<Reminder> reminderList = new ArrayList<>();

        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_REMINDERS + " WHERE " + KEY_SOURCE + "=?", args);

        // Cursor cursor = db.rawQuery(selectQuery, null);

        // Looping through all rows and adding to list
        if(cursor.moveToFirst()){
            do{
                Reminder reminder = new Reminder();
                reminder.setID(Integer.parseInt(cursor.getString(0)));
                reminder.setTitle(cursor.getString(1));
                reminder.setmSource(cursor.getString(2));

                // Adding Reminders to list
                reminderList.add(reminder);
            } while (cursor.moveToNext());
        }
        return reminderList;
    }

但仍然获得所有记录，而我只想获得属于来源的记录＆＃39; Online＆＃39;

Answer 1

尝试这种方式：

String[] args = new String[]{"Online"};
// For select
Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_REMINDERS + " WHERE " + KEY_SOURCE + "=?", args);

// For delete
Cursor cursor = db.rawQuery("DELETE FROM " + TABLE_REMINDERS + " WHERE " + KEY_SOURCE + "=?", args);

Answer 2

你可能想试试这个。它改编自我自己的sqlite代码。希望它有所帮助。

    private final String[] allColumns = {"id", "title", KEY_SOURCE}; 
     //or whatever your column name is

    String[] args = {"Online"};

    Cursor cursor =
            db.query(TABLE_REMINDERS, // a. table
                    allColumns, // b. column names
                    KEY_SOURCE + "=?", // c. selection
                    args, // d. selections args
                    null, // e. group by
                    null, // f. having
                    null, // g. order by
                    null); // h. limit

重要提示：与您的问题无关，但请记得调用cursor.close（）;使用完毕后。

Answer 3

Cursor findEntry = db.query（＆＃34; sku_table＆＃34;，columns，＆＃34; owner =？＆＃34;，new String [] {owner}，null，null，null）;

SQLite where子句问题

3 个答案: