表一：A  B    C D              表二： A  B    C E F G
      1 1997  8 2                     2 1987  5 3 1 1
      2         4                     4 1879  4 2 3 3
      3 1956  3 3                     5 1958  7 5 4 2
      4         2
      5         3
如何把表一合并到表二，使其变为以下形式：A  B    C D E F G
                                        1 1997  8 2
                                        2 1987  5 4 3 1 1
                                        3 1956  3 3
                                        4 1879  4 2 2 3 3
                                        5 1958  7 3 5 4 2
即表二里有的项不要被表一覆盖，把表二里没有的项加进来
求大神指点一下

谢谢版主，运行出来了