需求,查询两个表, 将值相减,存入另外一张表

今天做开发,需求是

        /**
         * 1.先获取查询lraccount账单表,
         * 2.查询数据预估表lrlistCollect表,
         * 3.二者相减存到lrpreAdjust账单调整表
         * 4.发送邮件
         */

初步就像写的逻辑是

            String sql01="select * from Lraccount where month= ";
            SSRS accoutSSRS = new ExeSQL().execSQL(sql01);

            
            String sql02="select * from Lraccount where month= ";
            SSRS listSSRS = new ExeSQL().execSQL(sql01);

            /**
             * 取最大的循环,对每一条进行判断
             * for(i,i<list){
             *         for(j,j<account){
             *             if(list.sno(i)==account.son(j){
             *                 insert(list.sno(i)-account.son(j));
             *                 将account中做过处理的条目插入临时templist    
             *                 break;
             *                 
             *              }
             *             对于list存在,而account不存在,将list(i)存入adjust
             *             insert(list(i)
             *         }
             * } #循环结束
             * 检查 account.row  和 templist.row 
             * if(account.row>templist.row){
             * 将 for(i<account){
             *         if(acount.sno(i)==templist.sno(i){
             *         continue;
             *         }else{
             *         insert(account(i));
             * }
             * 数据处理完毕
             * 发送邮件    
             * System.out.println(tSSRS.GetText(index, 3)+":::"+exeSql);            
             */
            // listSSRS 和 accoutSSRS
            List templist = new ArrayList();//临时数据表
            if(listSSRS==null || listSSRS.MaxRow<=0){
                if(accoutSSRS==null || accoutSSRS.MaxRow<=0){
                    
                }else{
                    for(int index=1;index<=accoutSSRS.MaxRow;index++){
                        System.out.println(accoutSSRS.GetText(index, 3));
                        //处理之后,insert();
                    }
                }
            }else{
                if(accoutSSRS==null || accoutSSRS.MaxRow<=0){
                    for(int index=1;index<=listSSRS.MaxRow;index++){
                        System.out.println(listSSRS.GetText(index, 3));
                        //处理之后,insert();
                    }
                }else{
                    for(int i=1;i<=listSSRS.MaxRow;i++){
                        for(int j=1;j<=accoutSSRS.MaxRow;j++){
                            if(listSSRS.GetText(i, 1)==accoutSSRS.GetText(j, 1)){
                                //相减,做插入操作
                                templist.add(accoutSSRS.GetText(j,1));
                            }else{
                                //list的数据做插入操作
                                
                            }
                        }
                    }
                    //处理account中的数据
                    if(accoutSSRS.MaxRow>templist.size()){
                        for(int i=1;i<=accoutSSRS.MaxRow;i++){
                            if(templist.contains(accoutSSRS.GetText(i,1))){
                                
                            }else{
                                //accountSSRS数据做负数处理,再insert()操作;
                            }
                        }
                    }
                }
            }

觉得逻辑好复杂,就像有简单的方法吗?自己想出来是使用sql语句进行逻辑判断和运算

  SELECT
    a.`list_id` AS id,
    a.`unicode`
    ,
    (IFNULL(a.`value`,0) - IFNULL(b.`value`,0)) AS dif
  FROM
    LIST a LEFT JOIN
    account b
  ON a.unicode = b.`unicode`
  
  UNION 
    SELECT
    b.`account_id` AS id,
    b.`unicode`
    ,
    (IFNULL(a.`value`,0) - IFNULL(b.`value`,0)) AS dif
  FROM
    LIST a RIGHT JOIN
    account b
  ON a.unicode = b.`unicode`

其中, list 和account 表分别为