Asked 7 years ago
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I want to get the sum of total rows in a column of a table in SqlLite Database. I am using GreenDao Library. I know I Have to use SUM
. But I don't know how to use it with GreenDao queryBuilder
. Can anybody help me? and also DISTINCT.
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1 Answer
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This is how I did it. Assume there is the Company entity and it has the numOfEmployees field:
Cursor cursor = daoSession.getDatabase().rawQuery("SELECT SUM(" + Company Dao.Properties.NumOfEmployees.columnName + ") FROM " + Company Dao.TABLENAME, new String []{});
cursor.moveToFirst();
long result = cursor.getLong(0);
Note that you could hardcode the column and table names above, but this is way cleaner.
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之前认为Apple 的iOS 设计的要比 Android 稳定,我错了吗?
下载的许多客户端程序/游戏程序,经常会Crash,是程序写的不好(内存泄漏?刚启动也会吗?)还是iOS本身的不稳定!!!
如果在Android手机中可以简单联接到ddms,就可以查看系统log,很容易看到程序为什么出错,在iPhone中如何得知呢?试试Organizer吧,分析一下Device logs,也许有用.