列表视图的 INNER JOIN 问题

Question

我有一个列表视图，当我在 on create 中调用 SQL 查询内部联接时，它什么也没做，也没有发生错误

        public Cursor getBankBranch() {
    Cursor cursor;
    SQLiteDatabase db = mDbHelper.getReadableDatabase();
    String selectQuery = "SELECT  * FROM " + DataEntry.BRANCH_TABLE_NAME + " INNER JOIN  " 
            + DataEntry.BANK_TABLE_NAME + " ON " 
            + DataEntry.BANK_TABLE_NAME + "." + DataEntry.COLUMN_BANK_ID + "  = " 
            + DataEntry.BRANCH_TABLE_NAME + "." + DataEntry.COLUMN_BRANCH_BANK_ID;
    cursor = db.rawQuery(selectQuery, null);
    cursor.moveToFirst();
    cursor.close();
    return cursor;
}

这是表格的内容

            String SQL_CREATE_BANK_TABLE = "CREATE TABLE " + DataEntry.BANK_TABLE_NAME + " ("
            + DataEntry.COLUMN_BANK_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
            + DataEntry.COLUMN_BANK_NAME + " TEXT );";

    String SQL_CREATE_BRANCH_TABLE = "CREATE TABLE " + DataEntry.BRANCH_TABLE_NAME + " ("
            + DataEntry.COLUMN_BRANCH_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
            + DataEntry.COLUMN_BRANCH_NAME + " TEXT , "
            + DataEntry.COLUMN_BRANCH_NUMBER + " TEXT , "
            + DataEntry.COLUMN_BRANCH_ADDRESS + " TEXT, "
            + DataEntry.COLUMN_BRANCH_BANK_ID + " INTEGER );";

    // Execute the SQL statement
    db.execSQL(SQL_CREATE_BANK_TABLE);
    db.execSQL(SQL_CREATE_BRANCH_TABLE);

Answer 1

您只是获取指向结果集的光标，然后将其移动到第一个结果，然后关闭它，但实际上并没有使用它。

让它工作的步骤

进行选择查询

String selectQuery = "SELECT ..."

执行查询获取光标

cursor = db.rawQuery(selectQuery, null);

创建一个 cursorAdapter

MyCursorAdapter adapter = new MyCursorAdapter(this, cursor);

设置ListView的适配器

list.setAdapter(adapter);

here is an example of how to use it