计算SQLite Android中的列总和

概述我需要计算Column的Sum值.为此,我正在使用以下查询.但是当我单击按钮进行计算时,应用程序崩溃了.Cursorcur=db.rawQuery("SELECTSUM"+(DbHelper.CART_TOTAL)+"FROM"+DbHelper.CART_TABLE,null);if(cur.moveToFirst()){Log.e("NetTotal",cur.getInt(0)

我需要计算Column的Sum值.为此,我正在使用以下查询.但是当我单击按钮进行计算时,应用程序崩溃了.

Cursor cur = db.rawquery("SELECT SUM " + (DbHelper.CART_TOTAL) + " FROM " + DbHelper.CART_table, null);if (cur.movetoFirst()) {       Log.e("Net Total", cur.getInt(0) + "");       return cur.getInt(0);         }        return 0;

Logcat错误：

      androID.database.sqlite.sqliteException:     no such column: SUM (code 1): , while compiling: SELECT SUM cart_total FROM cart_table                                                               at androID.database.sqlite.sqliteConnection.nativePrepareStatement(Native Method)                                                               at androID.database.sqlite.sqliteConnection.acquirePreparedStatement(sqliteConnection.java:882)                                                               at androID.database.sqlite.sqliteConnection.prepare(sqliteConnection.java:493)                                                               at androID.database.sqlite.sqliteSession.prepare(sqliteSession.java:588)                                                               at androID.database.sqlite.sqliteProgram.<init>(sqliteProgram.java:58)                                                               at androID.database.sqlite.sqlitequery.<init>(sqlitequery.java:37)                                                               at androID.database.sqlite.sqliteDirectCursorDriver.query(sqliteDirectCursorDriver.java:44)                                                               at androID.database.sqlite.sqliteDatabase.rawqueryWithFactory(sqliteDatabase.java:1314)                                                               at androID.database.sqlite.sqliteDatabase.rawquery(sqliteDatabase.java:1253)                                                               at com.insIDeglobe.restaurant.Db.DbUtil.calculateNetTotal(DbUtil.java:276)                                                               at com.insIDeglobe.restaurant.Adapter.MyCartAdapter.UpdateCart(MyCartAdapter.java:104)                                                               at com.insIDeglobe.restaurant.Adapter.MyCartAdapter.onClick(MyCartAdapter.java:91)                                                               at androID.vIEw.VIEw.performClick(VIEw.java:4084)                                                               at androID.vIEw.VIEw$PerformClick.run(VIEw.java:16987)                                                               at androID.os.Handler.handleCallback(Handler.java:615)                                                               at androID.os.Handler.dispatchMessage(Handler.java:92)                                                               at androID.os.Looper.loop(Looper.java:137)                                                               at androID.app.ActivityThread.main(ActivityThread.java:4794)                                                               at java.lang.reflect.Method.invokeNative(Native Method)                                                               at java.lang.reflect.Method.invoke(Method.java:511)                                                               at com.androID.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)                                                               at com.androID.internal.os.ZygoteInit.main(ZygoteInit.java:556)

解决方法:

正确的方法

 Cursor cursor = db.rawquery("SELECT SUM(" + DbHelper.CART_TOTAL + ") as Total FROM " + DbHelper.CART_table, null); if (cur.movetoFirst()) { int total = cursor.getInt(cursor.getColumnIndex("Total"));// get final total

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