Question

我正在同时学习android编程和sqlite。我正在创建一个像：

的表

    private static final String DATABASE_CREATE = "CREATE TABLE " + BOOK_TABLE + " ("
        + BookContract._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
        + BookContract.TITLE + " TEXT NOT NULL, "
        + BookContract.AUTHORS + " TEXT NOT NULL, "
        + BookContract.ISBN + " TEXT NOT NULL, "
        + BookContract.PRICE + " TEXT NOT NULL );";

在我的数据库中获取所有书籍的函数中，我的查询是：

String query =  "SELECT " +
            BOOK_TABLE + "." + BookContract._ID + ", " +
            BookContract.TITLE + ", " +
            BookContract.PRICE + ", " +
            BookContract.ISBN + ", " +
            "GROUP_CONCAT(" + AuthorContract.NAME + ", ',') as " + BookContract.AUTHORS +
            " FROM " + BOOK_TABLE + " LEFT OUTER JOIN " + AUTHOR_TABLE + " ON " +
            BOOK_TABLE + "." + BookContract._ID + "=" +
            AUTHOR_TABLE + "." + AuthorContract.BOOK_FOREIGN_KEY +
            " GROUP BY " + BOOK_TABLE + "." + BookContract._ID + ", " +
            BookContract.TITLE + ", " + BookContract.PRICE + ", " + BookContract.ISBN;

以下是创建表格时字符串的实际效果：

CREATE TABLE bookTable (_id INTEGER PRIMARY KEY AUTOINCREMENT, title TEXT NOT NULL, authors TEXT NOT NULL, isbn TEXT NOT NULL, price TEXT NOT NULL );

和查询：

 SELECT bookTable._id, title, price, isbn, GROUP_CONCAT(name, ',') as authors FROM bookTable LEFT OUTER JOIN authorTable ON bookTable._id = authorTable.book_fk GROUP BY bookTable._id, title, price, isbn

我发誓我对此感到疯狂，因为类似问题的类似stackOverflow帖子有轻微的拼写错误或缺少空格，但我的似乎在网上sql simulator上工作正常！

当我执行database.rawQuery(query, null)时，错误说 there is no such column: price appears in the log 。

编辑：

还有另一个作者表，其中包含评论中提到的缺少名称列，这里是为了清晰起见：

 String AUTHOR_TABLE_CREATE = "CREATE TABLE " + AUTHOR_TABLE + " ("
        + AuthorContract._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
        + AuthorContract.BOOK_FOREIGN_KEY + " INTEGER NOT NULL, "
        + AuthorContract.NAME  + " TEXT NOT NULL, "
        + "FOREIGN KEY ("+ AuthorContract.BOOK_FOREIGN_KEY+") " +
        "REFERENCES "+BOOK_TABLE+"("+BookContract._ID+") ON DELETE CASCADE);";

给出了字符串：

CREATE TABLE authorTable (_id INTEGER PRIMARY KEY AUTOINCREMENT, book_fk INTEGER NOT NULL, name TEXT NOT NULL, FOREIGN KEY (book_fk) REFERENCES bookTable(_id) ON DELETE CASCADE);

Answer 1

从移动设备卸载您的应用，然后重新运行。我希望如果代码没有问题，它会起作用。

SQLite没有这样的列，即使所有拼写正确并且间距正确

1 个答案: