Question

INTRODUCTION TO DATABASE TABLE BEING USED –

I am working on a “Stock Market Prices” based Database Table. My table has got the data for the following FIELDS –

ID
SYMBOL
OPEN
HIGH
LOW
CLOSE
VOLUME
VOLUME CHANGE
VOLUME CHANGE %
OPEN_INT
SECTOR
TIMESTAMP

New data gets added to the table daily “Monday to Friday”, based on the stock market price changes for that day. The current requirement is based on the VOLUME field, which shows the volume traded for a particular stock on daily basis.

REQUIREMENT –
To get the Average and Total Volume for last 10,15 and 30 Days respectively.

METHOD USED CURRENTLY –
I created these 9 SEPARATE QUERIES in order to get my desired results –
First I have created these 3 queries to take out the most recent last 10,15 and 30 dates from the current table:

qryLast10DaysStored
qryLast15DaysStored
qryLast30DaysStored

Then I have created these 3 queries for getting the respective AVERAGES:

qrySymbolAvgVolume10Days
qrySymbolAvgVolume15Days
qrySymbolAvgVolume30Days

And then I have created these 3 queries for getting the respective TOTALS:

qrySymbolTotalVolume10Days
qrySymbolTotalVolume15Days
qrySymbolTotalVolume30Days

PROBLEM BEING FACED WITH CURRENT METHOD –
Now, my problem is that I have ended up having these so many different queries, whereas I wanted to get the output into One Single Query, as shown in the Snapshot of the Excel Sheet:

http://i49.tinypic.com/256tgcp.png

SOLUTION NEEDED –
Is there some way by which I can get these required fields into ONE SINGLE QUERY, so that I do not have to look into multiple places for the required fields? Can someone please tell me how to get all these separate queries into one –
A) Either by taking out or moving the results from these separate individual queries to one.
B) Or by making a new query which calculates all these fields within itself, so that these separate individual queries are no longer needed. This would be a better solution I think.

One Clarification about Dates –
Some friend might think why I used the method of using Top 10,15 and 30 for getting the last 10,15 and 30 Date Values. Why not I just used the PC Date for getting these values? Or used something like –

("VOLUME","tbl-B", "TimeStamp BETWEEN Date() - 10 AND Date()")

The answer is that I require my query to “Read” the date from the “TIMESTAMP” Field, and then perform its calculations accordingly for LAST / MOST RECENT “10 days, 15 days, 30 days” FOR WHICH THE DATA IS AVAILABLE IN THE TABLE, WITHOUT BOTHERING WHAT THE CURRENT DATE IS. It should not depend upon the current date in any way.

If there is any better method or more efficient way to create these queries, then please enlighten.

Answer 1

Access doesn’t support most advanced SQL syntax and clauses, so this is a bit of a hack, but it works, and is fast on your small sample. You’re basically running 3 queries but the Union clauses allow you to combine into one:

select
   Symbol,
   sum([10DayTotalVol]) as 10DayTotalV,
   sum([10DayAvgVol]) as 10DayAvgV,
   sum([15DayTotalVol]) as 15DayTotalV,
   sum([15DayAvgVol]) as 15DayAvgV,
   sum([30DayTotalVol]) as 30DayTotalV,
   sum([30DayAvgVol]) as 30DayAvgV

from (

      select
        Symbol, 
        sum(volume) as 10DayTotalVol, avg(volume) as 10DayAvgVol,
        0 as 15DayTotalVol, 0 as 15DayAvgVol,
        0 as 30DayTotalVol, 0 as 30DayAvgVol
      from
         [tbl-b]
      where
         timestamp >= (select min(ts) from (select distinct top 10 timestamp as ts from [tbl-b] order by timestamp desc ))
      group by
         Symbol   

      UNION

      select
        Symbol, 
        0, 0,
        sum(volume), avg(volume),
        0, 0
      from
         [tbl-b]
      where
         timestamp >= (select min(ts) from (select distinct top 15 timestamp as ts from [tbl-b] order by timestamp desc ))
      group by
         Symbol    

      UNION

      select
        Symbol, 
        0, 0,
        0, 0,
        sum(volume), avg(volume)
      from
         [tbl-b]
      where
         timestamp >= (select min(ts) from (select distinct top 30 timestamp as ts from [tbl-b] order by timestamp desc ))
      group by
         Symbol 
      ) s

group by 
   Symbol