# Get Max of Each Category
**URL:** https://community.glideapps.com/t/get-max-of-each-category/67526
**Category:** Ask for Help
**Created:** [November 4, 2023, 6:32am UTC](https://community.glideapps.com/t/get-max-of-each-category/67526 "2023-11-04T06:32:15Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@RyanThomas](https://community.glideapps.com/u/RyanThomas)
#### Post date: [November 4, 2023, 6:32am UTC](https://community.glideapps.com/t/get-max-of-each-category/67526/1 "2023-11-04T06:32:16Z")
I am trying to make an app that will track truck and generator maintenance, logging mileage so that I can have a central place to check to see if a vehicle needs an oil change.
I already collect the mileage in another app, so I will have that data available to me.
Now I have a maintenance app where you will be able to log oil changes and other repairs. For now I only have a section for generators. Each generator has a specific barcode ID which is listed in the title.
If you click inside you can add oil changes and other repairs.
For the generators they need an oil change every 100 hours of use or every 6 months.
Right now, I’m trying to figure out how to get the max hour count from this maintenance table and have it filter results to only show a specific generator.
I can’t figure out how to get the maximum hour counter . Anyone have any insight?
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### Author:  [@Darren\_Murphy](https://community.glideapps.com/u/Darren_Murphy)
#### Post date: [November 4, 2023, 6:37am UTC](https://community.glideapps.com/t/get-max-of-each-category/67526/2 "2023-11-04T06:37:44Z")
Sounds like you need a Query column. If you can show me what your data tables look like I might be able to give you the exact configuration needed.
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### Author:  [@RyanThomas](https://community.glideapps.com/u/RyanThomas)
#### Post date: [November 4, 2023, 6:38am UTC](https://community.glideapps.com/t/get-max-of-each-category/67526/3 "2023-11-04T06:38:43Z")
I was playing with the Query field, had a feeling that might be it! I just edited my post, but here is the table for the generator maintenance.
I have a specific Row ID that corresponds with each generator.
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### Author:  [@Darren\_Murphy](https://community.glideapps.com/u/Darren_Murphy)
#### Post date: [November 4, 2023, 6:41am UTC](https://community.glideapps.com/t/get-max-of-each-category/67526/4 "2023-11-04T06:41:07Z")
So the goal is to get the Hour count from the most recent oil change for each generator?
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### Author:  [@RyanThomas](https://community.glideapps.com/u/RyanThomas)
#### Post date: [November 4, 2023, 6:43am UTC](https://community.glideapps.com/t/get-max-of-each-category/67526/5 "2023-11-04T06:43:28Z")
That is correct.
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### Author:  [@RyanThomas](https://community.glideapps.com/u/RyanThomas)
#### Post date: [November 4, 2023, 6:47am UTC](https://community.glideapps.com/t/get-max-of-each-category/67526/6 "2023-11-04T06:47:09Z")
I think I have it figured out now…you definitely put me on the right track with Query…I think my hang up was not putting this query on the main table with each generator. I was trying to do it in the table with all the maintenance before that had each individual hour count.
I did this Query…
And then this for the Rollup - Max column.
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### Author:  [@Darren\_Murphy](https://community.glideapps.com/u/Darren_Murphy)
#### Post date: [November 4, 2023, 6:53am UTC](https://community.glideapps.com/t/get-max-of-each-category/67526/7 "2023-11-04T06:53:31Z")
> [@RyanThomas](#):
>
> I think my hang up was not putting this query on the main table with each generator.
yep, that’s the key.
I was going to suggest order by Date limit one and then use a Single Value. But what you have looks fine.
You might want an extra filter in your Query (Service Done) if you will have other types of Service.
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### Author:  [@system](https://community.glideapps.com/u/system)
#### Post date: [November 11, 2023, 6:54am UTC](https://community.glideapps.com/t/get-max-of-each-category/67526/8 "2023-11-11T06:54:24Z")
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