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Jeremy CampbellFlag for United States of America

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Trying to calculate a percentage in an access query.

I am returning a few lines of data from my table. Each has an amount associated with it. I just want to return the selected items (through criteria on field [Seq]), then in another calculated field I'm trying to calculate each amount divided by the sum of specific amounts.

Here is a screenshot of what I'm trying to do;

User generated image
Here is that formula again;
Percentage: [LineItem]/(Sum(IIf([Seq]="1",[Amount],0))+Sum(IIf([Seq]="2",[Amount],0)))

When I try to run this I get the following error;
User generated image
Thanks for looking!
Avatar of Michael Carrillo
Michael Carrillo
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The first thing I have noticed is that you should select 'expression' for the table on the Percentage calculated field.

On the line directly below your formula click the empty field and select 'expression'.
Avatar of Jeremy Campbell

ASKER

This is not a totals query.. I don't have a dropdown where I can select expression:
As soon as you use 'Sum' this query became an aggregation query.
You can make this a totals query and for the fields that you are not totaling, you could make them where clauses that are visible and the value is not null.
I think I see what you were saying.. I had to manually click the Totals button in order for the drop down to show up.   Now I'm getting a data mismatch error.. Not sure why that is though..
I did just correct my Percentage formula.. It was using the incorrect field.. Should have been;

Percentage: [Amount]/(Sum(IIf([Seq]="1",[Amount],0))+Sum(IIf([Seq]="2",[Amount],0)))

Turns out this doesn't do what I want though.. It is not doing a sum of every line like I thought it would.
There is a problem.

If Amount is a number, say 50.
and the Seq = 1 then you would
calculate 50/0.  You cannot divide by zero.  that will throw an error.

Your If statement looks like it may be wrong.

if  seq=1
then Amount
Else 0

if seq=2
then amount
else 0

you are not summing anything.
Any idea how to get each line being returned by the query to divide by the sum of several lines of data? I thought that's what  Sum(IIf([Seq]="1",[Amount],0))+Sum(IIf([Seq]="2",[Amount],0))) was going to do for me.
The syntax for IIF is

IIF( condition, True, False)

What you did is string several IIF statements together, but they don't sum.

It looks like you truly do want to do a totals query. So you need to group off one or more of your fields.  Then you would have a simple sum that you could use in your percentage calculation.
When you are trying to total the amounts for the percentage.  What characterizes that group of records together? Are they the same Category?
In this case yes they are the same category.. I'm putting a quick screenshot together that will better represent the output I'm trying to get.
Okay.. Maybe this will help identify what I'm trying to accomplish.. This is a screenshot of the exact output I'm trying to get to.. Is this possible in one query?

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ASKER CERTIFIED SOLUTION
Avatar of Michael Carrillo
Michael Carrillo
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Avatar of Jeffrey Coachman
SeyerIT,

Is it a coincidence that the sum of 1 and 2 is the same as the total for 3?

Are all the percentages supposed to be *Only* compared to the total of 1 and 2 as a percent?
(ex: 4 is 133% of one and two.)

In other words can you post more sample data, and make it more "random".

As always a sample DB is always much clearer.

If your goal here is to simply calculate the percentage that each line item is of the total then you can try something like this:

Create a public function in a module:
Public Function GetPercent(Amount As Currency) As Double
Dim dblTotal As Double
    dblTotal = DSum("Amt", "YourTable")
    GetPercent = Amount / dblTotal
End Function

Then call this in your query as a new field:
SELECT YourTable.ID, YourTable.Cat, YourTable.Item, YourTable.Amt, GetPercent([Amt]) AS PCT
FROM YourTable;
Database68.accdb
This was perfect! Sorry I'm just getting back to you on this. Boag, give me a second and I'll follow up and explain.
Boag, It was just a coincidence that those number equaled out the way they did. I didn't want it to appear that I was just taking the percentage by the sum of only the visible lines in the query and that they may come from other lines as well. My end query for this one was actually including the sum of Seq 1,2,3 & 4 but that wasn't going to be the case on the next one.

Thanks for your help though! Your always very good at guiding me to a better description of my problems so I can get through these :)
No problem, again, as long as you got the solution you needed, then it's all good...