query statement weighted avg multiple tables

[jrtaylor]

My site has numerous tables. Each table contains monthly data of various investment programs. While my general "template" is to cover a 4 year period, not all programs will have a full 4 year's worth of data.

For example:

Program A Inception: 6/08
Program B Inception: 4/09
Program C Inception: 9/09

I'd like to add a feature to my site which allows users to "mix and match" investments to see what their return might be if (for example) they had invested in

Program A: $ 5,000
Program B: $10,000
Program C: $12,000

The results would be shown via google graphs.

We would assume the investments are made according to the first date where there's data.

Could someone guide me on the code for this? I'm new to Php. If this were an excel spreadsheet I could do it in a heartbeat, but PHP remains foreign to me!

Thanks Much.

[sfullman]

I've done some averaging and summing, and I think you need to get familiar with the SQL part for this eventually.

given a table:

returns
---------
programID
postdate (e.g. 2008-01-01)
amount

you can use the mysql function DATE_DIFF() and DATE_SUB() I believe, you may also get

SELECT programID, MIN(postdate) AS ProgramStart,
MAX(postdate) AS ProgramEnd
FROM returns 
GROUP BY programID

and use those values anywhere in your query.

I know I have given you a general reply, but in fairness, you have asked a general question 🙂 As you begin to work through specific queries post them here or elsewhere for further direction.