Question

我有以下查询返回12个月的数据。最初的查询是14天，我用datediff方法改变了一天到一个月来获得14个月的数据，但我只获得了12个月的数据。任何人都可以检查，看看为什么？

Select 'playing' As activity 
--,ad.xDate 
,min(ad.xDate) As xDate
,Isnull(sum(t.TimePerDay),0) As TimePerDay 
From    AllDates As ad With (Nolock) 
Left Join @test As t On ad.xDate = t.date
GROUP BY datepart(Month, ad.xDate)
--ORDER BY YEAR(datepart(Month, ad.xDate)) DESC, MONTH(datepart(Month, ad.xDate)) DESC, DAY(datepart(Month, ad.xDate))
ORDER BY MIN(ad.xDate)
option (maxrecursion 0)
END

Answer 1

2件事：

@LastXMonths = -14

@MinDate所以@MaxDate仅在GROUP BY datepart(Month, ad.xDate)之前13个月。

接下来，这句话：

+1

它会返回1到12之间的数字，所以你永远不会超过12个月。

解决方案：

删除第一个语句中的Select 'playing' As activity ,ad.xDate ,Isnull(sum(t.TimePerDay),0) As TimePerDay From AllDates As ad With (Nolock) Left Join @test As t On ad.xDate = t.date GROUP BY ad.xDate ORDER BY ad.xDate option (maxrecursion 0)，并将最终选择更改为：

 public class First_Fragment extends Fragment {

        View myView;
        TextView tv;
        @Nullable
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            myView = inflater.inflate(R.layout.first_layout, container, false);
         tv = (TextView) myView.findViewById(R.id.textView2);
            return myView;


        }



        public boolean executeCommand(){
            System.out.println("executeCommand");
            Runtime runtime = Runtime.getRuntime();
            try
            {
                Process  mIpAddrProcess = runtime.exec("/system/bin/ping -c 1 8.8.8.8");
                int mExitValue = mIpAddrProcess.waitFor();
                System.out.println(" mExitValue " + mExitValue);
                if(mExitValue==0){
                    return true;
                }else{
                    return false;
                }


                tv.setText(mExitValue);

            }
            catch (InterruptedException ignore)
            {
                ignore.printStackTrace();
                System.out.println(" Exception:"+ignore);
            }
            catch (IOException e)
            {
                e.printStackTrace();
                System.out.println(" Exception:"+e);
            }
            return false;


        }

    }

Answer 2

您需要按ad.xDate的月份和年份分组。一年只有十二个月你应该看到你的结果最早的两个月（14 - 2）月总数太大，因为它们实际上代表了两个日历月的组合。

它适用于您的原始版本，因为任何月份都有超过14天。如果您尝试将旧查询扩展超过31天（或28或29，30几个月），那么您会再次发现同样的问题。

...
SELECT
    'playing' As activity,
    min(ad.xDate) As xDate, 
    Isnull(sum(t.TimePerDay), 0) As TimePerDay
FROM AllDates As ad Left Outer Join @test As t On ad.xDate = t.date
GROUP BY Year(ad.xDate), Month(ad.xDate) /* <--- change here */
ORDER BY xDate

为什么以下SQL Server查询返回12个月的数据而不是14个月的数据

2 个答案:

解决方案：