I am new to Glide building my first app. The app is intended to collect water meter readings at water treatment facilities on a daily basis. The app needs to calculate the water flow on a daily basis, which is fetching the previous day meter reading and subtracting it from the current days reading. …

Is someone gonna add data by hand somewhere? Do you want the calculation on new added row or on a daily schedule automatically?

You would use a variation of this. [image] Diffferent formula from Row 2 onwards Ask for Help Make sure you record the user’s ID/email. Use a query column, filter by user’s ID/email equals to this row > user’s ID/email. Add a rowID column to your table. Add a lookup colum…

@MaximeBaker Yes, there are operators that visit the facilities on a daily basis and they will key the meter readings into the app. The calculation can go on the new row but I will be referencing it at some point to add it to a monthly report. Thanks

Thanks @Jeff_Hager I will check that out.

@Jeff_Hager I followed your steps and I was able to create the index for the previous row. I am at this point: Add a query column, use the query from the 2nd step as a base, filter by index equals to this row > previous row’s index. Add a single column to fetch the first “EndBal” from the query ab…

So if you create a query column, you can point it at the same table and set the filter in the query to return rows where the Index matches the ‘this row’ prior index (index-1). Personally for this use case, I would just create a relation instead which will be a simpler and a run a little faster. J…

@Jeff_Hager awesome! that worked, thanks so much for your help!

@Jeff_Hager I thought I had it solved, but as I started adding meter readings to the table for different facilities, the relation I set up failed to work properly. I have created a simple version of my table below. The issue is that the “Index Relation” keeps referring to the first facility. In oth…

[image] bmagnotta: The issue is that the “Index Relation” keeps referring to the first facility. Since you have multiple facilities, you will need to use the Query and Single Value method so you can filter the query by multiple values such as facility AND prior index.

Haven’t been following this thread too closely, but I think the below video might help: https://www.loom.com/share/042be3be13004355b0dedec1be67b400

Fetching data from a previous row using date

Ask for Help

Jeff_Hager January 9, 2025, 3:06am 3

You would use a variation of this.

Topic		Replies	Views
Calculating between two rows // Water Metering App Ask for Help	11	604	August 10, 2022
User based previous date Ask for Help	7	328	November 11, 2021
Calcul entre deux rows Ask for Help	5	210	June 21, 2024
Conditional Relations Feature Requests	23	3520	May 4, 2023
Pulling Data into one row Ask for Help	3	366	January 15, 2022

Fetching data from a previous row using date

Related topics