android内容提供商总和查询 [英] android content provider sum query

问题描述

我想要sum(column)时可以使用getContentResolver().query()吗?

或

我必须对数据库句柄进行原始查询吗?

Do I have to make raw query to db handle?

推荐答案

好的，看来使用getContentResolver().query()是不可能的. 我必须建立数据库连接并建立rawQuery.

OK, it seems that its not possible using getContentResolver().query(). I had to get db connection and make rawQuery.

 ContentProviderClient client =  getContentResolver().acquireContentProviderClient(AUTHORITY);
 SQLiteDatabase dbHandle= ((MyContentProvider)client.getLocalContentProvider()).getDbHandle();
 Cursor cursor = dbHandle.rawQuery("SELECT sum("+COLUM_NNAME+") FROM "+TABLE_NAME +" WHERE "+WHERE_CLAUSE , null);
 cursor.moveToFirst();
 int cnt =  cursor.getInt(0);
 cursor.close();
 cursor.deactivate();
 client.release();

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