[RESOLVED] Up for a Challenge

rontgoff

I need to apply certain prices to certain groups of numbers and for the life of me can't figure out the solution. So I am posting the challenge here to see if anyone wants to give it a try.

Here's what I got

Person pre bought units and the price they were purchased
400 @ $0.10
400 @ $0.20
500 @ $0.05

Amount of units person has used at a specific time
25
25
25
25
300
100

What is needed is how much each unit cost at the time it was used.

So the first 5 times the units were used they cost $0.10.

The next 100 will be used at a cost of $0.20

So it would show
25 @ $0.10
25 @ $0.10
25 @ $0.10
25 @ $0.10
300 @ $0.10
100 @ $0.20

Total amount $ spent

So how would you have PHP caluclate the total, it's very confusing.

bpat1434

umm... not sure but possibly:

$i = 1;

switch(TRUE)
{
  case ( ($i>0) && ($i<=100) ):
    echo '$0.10 / piece';
    break;
  case ( ($i>100) && ($i<=400) ):
    echo '$0.10 / piece';
    break;
  case ( ($i>400) )
    echo '$0.20 / piece';
    break;
}

Something like that? Not sure as to what you're getting at.

}

justsomeone

I'm not sure I fully understand either. But I'm guessing that what you want to achieve is slightly different to what bpat1434 has come up with.

If I understand you correctly, you want to be able to record the "cost price" of these widgets and reflect this when they are used. The "cost price" can potentially be different every time they are purchased.

To do this you would need to build in a purchasing history into an inventory control system.

This might need a table something like

USER_ID, PRODUCT CODE, PURCHASE_DATE, UNIT_COST, NUMBER_PURCHASED, NUMBER_REMAINING

every time the user purchases some widgets, you store a record in here.

So, if user 102 bought 100 of product code 1234 at $10 each on Tuesday, this would look something like:

102, 1234, 2006/01/24, 10.00, 100, 100

If they bought a further 100 @ $11.50 on Wednesday, a further record would be added

102, 1234, 2006/01/25, 11.50, 100, 100

The table now looks like

102, 1234, 2006/01/24, 10.00, 100, 100
102, 1234, 2006/01/25, 11.50, 100, 100

Now, if user 102 "uses" 75 of these widgets, this table can be search to find the "oldest" 75 widgets in the data base. In this case, they are all from Tuesday's batch. This would mean that the first record would need to be updated to reflect the usage of 75. The table now looks like this:

102, 1234, 2006/01/24, 10.00, 100, 25
102, 1234, 2006/01/25, 11.50, 100, 100

Now, imagine the user comes back to use a further 50 widgets. Again, you search the database for the oldest supply of widgets, and you see that there are 25 remaining in Tuesday's batch. You update this to reflect that you are now using 25 of them. Now you start your search again, and you find that the oldest supply dates from Wednesday, so you update that record to reflect that a 25 of these have been used.

102, 1234, 2006/01/24, 10.00, 100, 0
102, 1234, 2006/01/25, 11.50, 100, 75

Does this sound like what you want?

rontgoff

Thanks ~Brett but justsomeone is right on.

The variables are not static and will change constantly.

justsomeone I am pulling out of the database and I understand what you're saying but this is where the problem lies. There is a year and half of stored info. I was hoping there was some way of going through and doing the calculations on a page and not at the DB level since we can't go back and adjust the info.

justsomeone

What information do you have which you can base your calculations on? How can you maintain this information in the future?

I don't see how you can do it all "on a page", as the page can't "remember" how many units are left - this running total needs to be stored someplace.

rontgoff

I kind of figured that was the case I thought I'd see if there was a way. I've been banging my head on the wall with the data trying so many different ways. I will implement storing the price per unit at a db level. thanks for trying