SQLite where 子句问题

Question

我在 SQLite table 中有大约 30 条记录，其中 10 条记录属于在线的来源，其余 20 记录属于来源 Offline.

现在，我想从 Online 中获取属于 source 的所有 records，为此我写了这个：

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

但是通过使用上面的查询，我得到了数据库中可用的所有记录，无论它属于离线还是在线

所以我错了，为什么我无法获取仅属于源“Online”的数据

而，我使用下面的查询从属于 source 'Online' 的 table 到 delete data，它对我有用：

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;
    }

但仍然获取所有记录，而我只想获取属于源的记录'Online'

Answer 1

试试这个方法：

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

游标 findEntry = db.query("sku_table", columns, "owner=?", new String[] { owner }, null, null, null);

Answer 3

你可能想试试这个。它改编自我自己的 sqlite 代码。希望对你有帮助。

    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，但请记住调用 cursor.close();使用完毕后。

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