How to determine which customer bought the items based on price - mysql

Question

I have two tables called transdt and inv_sldtl.
The transdt table consists of the customer ID and the total price of the items that customers bought.
+----------+-----------+-----------+------------+------------+----------+
| BranchID | TransCode | ControlNo | CustomerID | Date | Amount |
+----------+-----------+-----------+------------+------------+----------+
| 1 | 48 | 469 | 1170 | 2017-05-01 | 295.00 |
| 1 | 48 | 469 | 1185 | 2017-05-01 | 44257.24 |
+----------+-----------+-----------+------------+------------+----------+
and the inv_sldtl contains the item id, unit cost, quantity and total cost.
+----------+-----------+--------+-----------+------------+----------+----------+-----------+
| BranchID | TransCode | ItemID | ControlNo | Date | Quantity | UnitCost | TotalCost |
+----------+-----------+--------+-----------+------------+----------+----------+-----------+
| 1 | 48 | 108 | 469 | 2017-05-01 | 1.00 | 45.00 | 45.00 |
| 1 | 48 | 736 | 469 | 2017-05-01 | 10.00 | 25.00 | 250.00 |
| 1 | 48 | 622 | 469 | 2017-05-01 | 4.00 | 280 | 1120.00 |
| 1 | 48 | 500 | 469 | 2017-05-01 | 4.00 | 10784.31 | 43137.24 |
| | | | | | | | |
+----------+-----------+--------+-----------+------------+----------+----------+-----------+
Given that the results of two tables are in same one transaction which is determined by the ControlNo.
Is there any way we can output like this?
+-----------+-----------+------------+--------+------------+
| ControlNo | TransCode | CustomerID | ItemID | Date |
+-----------+-----------+------------+--------+------------+
| 469 | 48 | 1170 | 108 | 2017-05-01 |
| 469 | 48 | 1170 | 736 | 2017-05-01 |
| 469 | 48 | 1185 | 622 | 2017-05-01 |
| 469 | 48 | 1185 | 500 | 2017-05-01 |
+-----------+-----------+------------+--------+------------+
I assume that we can determine it based on the Amount in transdt table and TotalCost in inv_sldtl table. But how?
EDIT: Since SQL seems doesn't have a solution for this, How can I achieve this using VB6 as my programming language as what #ThorstenKettner have told?
Thanks :)

Answer 1

You would have to build all item combinations in order to compare these with the customers' totals.
pack #1 | pack #2 | sums
-----------+------------+-----------------
item 1 | item 2+3+4 | 45.00 , 44507.24
item 1+2 | item 3+4 | ...
item 1+3 | item 2+4 | ...
item 1+4 | item 2+3 | ...
item 1+2+3 | item 4 | ...
item 2 | item 1+3+4 | ...
item 2+3 | item 1+4 | ...
...
This is no task for SQL. At least not for a DBMS that doesn't support recursive queries. So use a programming language instead. I.e. use Java, C#, whatever, read the data, then get your totals by calling a recursive function.
UPDATE: You have asked for further help on the algorithm. Here is one possible way:
You have a set of n customers, here (1170,1185).
You have a set of m items, here (108,500,622,736).
Take the customer with the lowest total, here customer 1170 with 295.00.
Find item combinations matching the price. You'd use a recursive function call and stop as soon as the price is too high. So you quickly end up with item 108 = 45.00, item 736 = 250.00 and items 108+736 = 295.00. Only the last combination is a match.
Remove the customer from the cusomer set. Remove the item(s) from the item set.
Continue with step 3, till you are done.
To make this a tad more complicated: You see that you can have multiple matches for a customer, e.g. both items A + B and items B + C + D match the customer total. So step 5 and following must be done for every match. Another recursion :-)
Do this slowly, step by step, so as not to get confused. Good luck :-)

Answer 2

Without knowing exactly what you want and if you have Primary or Foreign keys which if you don't should have your ControlNo in first table transdt the PK and FK in your inv_sldt1 so that you can use something like my code below. This way you can also link the tables together by some column. Anyways again without seeing everything here is what I came up with on the fly check it out and let me know.
SELECT CustomerID, Date, Quantity
FROM transdt
INNER JOIN inv_sldt1 ON transdt.ControlNo=inv_sldt1.ControlNo
WHERE ItemID = 108