android - SQLiteDatabase - 如何使用 where 子句？

Question

public Cursor fetchTimetable() {
    return mDb.query(DATABASE_TABLE_TIMETABLE, new String[] {TIMETABLE_ROWID,    TIMETABLE_MODULECODE, TIMETABLE_MODULENAME, TIMETABLE_ROOM, TIMETABLE_LECTURER, TIMETABLE_TIME}, null, null, null, null, null);
}

例如，如果我想要 TIMETABLE_MODULECODE = 123。我该怎么做，我已经读取了它的第一个空值。我已经在下面尝试过了，但仍然不起作用

public Cursor fetchTimetable() {
    String a = "TIMETABLE_CODE = ADD";
    return mDb.query(DATABASE_TABLE_TIMETABLE, new String[] {TIMETABLE_ROWID, TIMETABLE_MODULECODE, TIMETABLE_MODULENAME, TIMETABLE_ROOM, TIMETABLE_LECTURER, TIMETABLE_TIME}, a, null, null, null, null);
}

Answer 1

我使用 where args 的工作示例(使用它更清楚):

        String [] settingsProjection = {
                DBContract.Settings._ID,
                DBContract.Settings.COLUMN_NAME_USER_ID,
                DBContract.Settings.COLUMN_NAME_AUTO_LOGIN
        };

        String whereClause = DBContract.Settings.COLUMN_NAME_USER_ID+"=?";
        String [] whereArgs = {userId.toString()};

        Cursor c = db.query(
                DBContract.Settings.TABLE_NAME,
                settingsProjection,
                whereClause,
                whereArgs,
                null,
                null,
                null
        );