Existing a MDB database (variation. MDB), there were four tables, the format of the former three tables are exactly the same, the fourth table want to do a summary, and need some calculations,

Specific operation is as follows:
1, table 1 (table named variation) intact copy to table 4 (table named variation_4), said the figure 1 copy all the contents of blue box to table 4 blue box;
(table 2, table 2 called variation_2) in each record in the table 4 and compare the before each of the nine bar, if "tube core number", "test group", "test project", "pin number", "test values lower limit", "maximum test", "unit" on all fours, write your "test values in table 2 to table 4" test values - 2 "position of corresponding items, and computing" test values "and the difference in value between" test values - 2 "(" test values" - "test values - 2"), it is concluded that the difference of fill in the table 4-2 "difference" column;
3, (similar to a), in table 3 (table named variation_3) in each record in the table 4 and compare the before each of the nine bar, if "tube core number", "test group", "test project", "pin number", "test values lower limit", "maximum test", "unit" on all fours, will the "test values in the table 3 to fill in the table 4" test values - 3 "position of corresponding items, and computing" test values "and the difference in value between" test values - 3 "(" test values" - "test values - 3"), it is concluded that the difference of fill in the table 4-3 "difference" column;
4, if the table 2 is empty, table 3 is not null, only steps 1, 3, If you don't empty table 2, table 3 is empty, only steps 1, 2,
5, if the table 2 or table 3 and table 4 each going on each of the 9 column before compares, no match, then on to the next article, do not need to make a prompt,

Please pass the great god and moderator told this sentence how to write, here first thank humbly,

In addition, once appear in table 1 and table 2, table 3 each have more than 4 million data limit, the time variation. The MDB file has reached around 1.3 G, trouble in. Write a program to consider when comparing efficiency,

Thanks,

Link: https://pan.baidu.com/s/1I6WPPMjavc_VjFLXmvXldA
The extracted code: n6k5