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calculating totals from specific records


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Hi,

 

I cannot figure out how to calcuate a total_length field that can be stored so I can use it in another calculations.

 

I need to find a percentage of something within a length of transect I walked. The transect is broken into multiple units. Each unit has its own number and date. There are multiple records in my database with different units/dates, but I need to calculate a stored data field for the entire unit length of my individual transects so I can determine the total percentage of substrates, etc, along only that transect- not others.

 

The first thing I tried to do was when I created the cumulative length field, I clicked "summary" and then "fraction of the total of." The issue is that I am only allowed to click one subtotal field to link those records to my particular result. I really need to click two fields (date AND unit name) to make the database pull the correct records to be totaled. 
 

How do I do this??? Thanks so much.

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I deleted your other post as a duplicate of this one. Please do not double post your questions.

 

It appeared that you might have encountered a hiccup in the system and thought that it hadn’t posted or something.

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Thanks for doing that. I apologize for posting twice. A hiccup. I'm trying to create calculations based on data collected along different reaches of streams. The calculations are sort of complex. For instance, I need to calculate the percent of combined substrates for the entire area of each stream. Since the streams are separated into units, I need to calculate the area for each unit and then find the cumulative totals. My problem is that the cumulative totals are required in my calculation, but the calculations don't work. Do I need to use the Get Summary function? I don't know how to use it. 

 

I'm sure this is clear as mud. Thanks for your help!

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I'm sure this is clear as mud.

 

I am afraid at the moment that is quite true. We need a much clearer description of (1) what you have and (2) what do you need to get out of it (the part of what you tried and didn't work is only distracting).

 

 

The transect is broken into multiple units. Each unit has its own number and date.

 

I believe that means you have (or should have) a table of Transects and a table of Units, related by TransectID. And the Units table has fields for UnitNumber and Date.  And Length? That's all I could figure out.

 

 

When you mention other things like substrates, streams, etc., you need to tell us what they are, in terms of tables and fields - and how are they related to the other objects tracked by your solution.

 

 

Now, to calculate the total length of a transect's units, you could use a calculation field in the Transects table =

Sum ( Units::Length ) 
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