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Thread: java computation issue

  1. #1
    Junior Member datathinker's Avatar
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    Default java computation issue

    Question background:

    One Bank Information System needs to figure out mobile average(MA)( On the chart, the mobile average is a trend line which smoothes the recurrences of the days and provides you with a quick overview of the period trend) amount of monthly loan from Loan Table defined as below,


    Time amount
    3/14/2011 $43,334.10
    3/15/2011 $92,304.10 ...
    3/16/2011 $45,983.80 ...
    3/17/2011 $36,973.10 ...
    3/18/2011 $24,987.87 ...
    ... ... ...
    It is easy for SQL to calculate monthly loan by grouping by. But I don't know how to make it out with sql as relative location and cross row computation are involved , Soppose we do it purely with java, following the codes:
    st=conn.prepareStatement("select sum(amount)amount, to_char(time,'MM')month from loan  where to_char(time,'yyyy')=to_char(sysdate,'yyyy') group by to_char(time,'MM') order by month",ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
    			ResultSet rs=st.executeQuery();
    			int size=rs.getFetchSize();
    			for(int currentPos=1;currentPos<=size;currentPos++){
    				rs.absolute(currentPos);
    				float preAmount=-1,thisAmount=-1,nextAmount=-1;
    				float avgAmount=-1;
    				String month=rs.getString("month");
    				thisAmount=rs.getFloat("amount");
    				if(currentPos==1){	
    					rs.next();
    					nextAmount=rs.getFloat("amount");
    					avgAmount=(thisAmount+nextAmount)/2;
    				}else if(currentPos==size){
    					rs.previous();
    					preAmount=rs.getFloat("amount");
    					avgAmount=(thisAmount+preAmount)/2;
    				}else{
    					rs.previous();
    					preAmount=rs.getFloat("amount");
    					rs.next();
    					rs.next();
    					nextAmount=rs.getFloat("amount");
    					avgAmount=(thisAmount+nextAmount+preAmount)/3;
    				}
    				System.out.println(month+"   "+avgAmount);	
    			}
    			rs.close();
    ....
    Except pure java coding, I think this kind of data process job could also be done by sql or esProc and maybe esProc will be easier. But I don't know too much about sql, hope people viewing my thread could give some tips.


  2. #2
    Crazy Cat Lady KevinWorkman's Avatar
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    Default Re: java computation issue

    Are you asking how to do this using SQL? This is a Java forum, not a SQL forum.

    I can move this thread to the "other languages" forum and hope somebody knows more about SQL if you want, but I'd suggest posting on a SQL forum instead. Make sure you link between crossposts though.
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