两表整合的问题

Question

已有表：
表名   工作量录入
                                                                                                                                                               
日期                    人员          人员2          人员3   .........           工作内容                     得分         得分2
                                                                                                                                                               
五月1日             张三            李二           NULL    .......      （每人出勤+内容1）              450           452
五月1日            李四             NULL           李二      .......      （每人出勤+内容2）            460           468
五月2日            王五            NULL         NULL    .......        （每人出勤+内容3）                  500           123
五月2日            王二            NULL         NULL     ........       （每人出勤+内容4）                501           193
...  ...........           ........               .........        .............             ............                       .......           ...... .... 
                                                                                                                                                               
表名  人员每日得分表                                                                                                                                                               
日期                    张三            李二         李四            张凯            王五          王二          .........           
五月1日
五月2日
五月3日
五月4日
                                                                                                                                                               希望得到下面的结果                                                                                                                                                               
日期                    张三            李二         李四            张凯            王五          王二     .............                
                                                                                                                                                               
五月1日             450            920             460           468                   
五月2日           NULL           NULL         NULL       NULL               500          123...  ...........           ........               .........        .............             ............                       .......           .......... 
在五月1日 李二有两次出勤分 每天只能有一次出勤，所以要减去 只保留1个出勤分：20分
                                                                                                                                                               
     

Answer 1

日期                    张三            李二         李四            张凯            王五          王二     .............                
                                                                                                                                                               
五月1日             450            920             460           468                   
五月2日           NULL           NULL         NULL       NULL               500          123...  ...........           ........               .........        .............             ............                       .......           .......... 
在五月1日 李二有两次出勤分 每天只能有一次出勤，所以要减去 只保留1个出勤分：20分
到底是 920 ，还是 20 ？