Report and Graphic in access 2007 - calculating values on queries - ms-access

Question

Picture a table with fields (Id, Valid, Value)
Valid = boolean
Value = number from 0 to 100
What I want is a report that counts the number of records where (valid = 0), and then gives me the total number of cases where (value < 70) and the number of cases where (value >= 70).
The problem is that the "value" field could be empty on some of the records and I only want the records where the value field is not empty.
I know that the second value (value>=70) is going to be calculated, but the problem is that I can't simply do (total number of records - number of records where value < 70), because there's the problem with the records where "value" is null...
And then I want to create graphic with these values, to see the percentage of records below and above 70.

Answer 1

"The problem is that the "value" field could be empty on some of the records and I only want the records where the value field is not empty."
Use a WHERE clause to exclude rows whose "value" field is Null.
Here is sample data for tblMetraton.
Id Valid Valu
1 -1 2
2 0 4
3 -1 6
4 0
5 0 90
I used Valu for the field name because Value is a reserved word.
You can use the Count() function in a query and take advantage of the fact it only counts non-Null values. So use Count() with an IIf() expression which returns a non-Null value (I used 1) for the condition you want to match and Null otherwise.
SELECT
Count(IIf(Valid=0,1,Null)) AS valid_false,
Count(IIf(Valu<70,1,Null)) AS below_70,
Count(IIf([Valu]>=70,1,Null)) AS at_least70
FROM tblMetraton AS m
WHERE (((m.[Valu]) Is Not Null));
Based on my sample data in tblMetraton, that query gives me this result set.
valid_false below_70 at_least70
2 3 1
If my sample data does not address the variability you're dealing with, and/or if my query results don't match your requirements, please show us you own sample data and the results you want based on that sample.