如何在android中使用rawQuery（）

Question

我有像这样的SQL查询

String loadFav = "SELECT _id, title, name, favorite FROM table1 where favorite= 1 " 
                     + "UNION ALL" 
                     + "SELECT _id, title, name, favorite FROM table2 where favorite= 1"
                     ;

    Cursor mCursor = mSQLiteDatabase.rawQuery(loadFav, null);

运行此查询时出错。这是正确的结构吗？有人能帮助我吗？

Answer 1

始终通过查看SQL字符串进行故障排除 - 而不是构建SQL字符串的代码！

SELECT _id, title, name, favorite FROM table1 where favorite= 1 UNION ALLSELECT _id, title, name, favorite FROM table2 where favorite= 1

ALL和第二个SELECT之间需要一个空格。