Access Histogram query example - you'll be surprised at how easy it is to do
the calculations for a seemingly complex statistical measure using a single Access query. In this
example we have customers who purchased items from a store.
15 years ago we were putting Access database on the web using Active Server Page (ASP) programming language for the user interface. See examples of Access on the Internet.
We want to know the distribution of customer purchases grouped by customer's age.
To start, we have a table called M_Customer_Purchases (in reality this would
probably be a query based on a Customer table and a Purchases table).
The table has 2 fields (the purchase_date field is really
not required for this example).
The following sql statement will group the ages (purchases)
into 6 categories based on the customer's age. You can see the
bracketing of the age in the immediate if statement (iif) - this created the Access histogram values.
Sum(IIf([Age]<18,1,0)) AS Group1,
Sum(IIf([Age]>=18 and [Age]<30,1,0)) AS Group2,
Sum(IIf([Age]>=30 and [Age]<40,1,0)) AS Group3,
Sum(IIf([Age]>=40 and [Age]<50,1,0)) AS Group4,
Sum(IIf([Age]>=50 and [Age]<60,1,0)) AS Group5,
Sum(IIf([Age]>=60,1,0)) AS Group6
The following is the result of the Access example query. You could easy pass this
query to a bar chart to display the results graphically.
Note the trick is the 1, 0 in the iif statement - when the age matches the
age range in the iif statement then the result is one, otherwise the result is
0, thereby providing a way to SUM the results.
You should be able to see how you can bracket results for all kinds of
data. You could bracket date ranges to simulate a crosstab query (pivot query).
One advantage of using the method in this example over crosstabs is that you
can pass query parameters to the query from a form field.
combine this query technique for histogram calculations with our bar chart
example. The code in the bar chart example will work with forms or
Go to our download center to download and run the
Bar Chart/Bar Graph example.