# Subtract values from different measurements

**URL:** <https://community.influxdata.com/t/subtract-values-from-different-measurements/28130>\
**Category:** Systems\
**Tags:** query, flux\
**Created:** [January 13, 2023, 11:04am UTC](https://community.influxdata.com/t/subtract-values-from-different-measurements/28130 "2023-01-13T11:04:22Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Johan\_Granqvist](https://sea1.discourse-cdn.com/flex023/user_avatar/community.influxdata.com/johan_granqvist/32/11846_2.png) [@Johan\_Granqvist](https://community.influxdata.com/u/Johan_Granqvist)\
**Post date:** [January 13, 2023, 11:04am UTC](https://community.influxdata.com/t/subtract-values-from-different-measurements/28130/1 "2023-01-13T11:04:22Z")

</div>

I want to subtract one value from another from different measurements. Boths values are floats. I am following the article here: [https://www.influxdata.com/blog/influxdb-how-to-do-joins-math-across-measurements/](https://www.influxdata.com/blog/influxdb-how-to-do-joins-math-across-measurements/)  
I am a noob at fluxql which i use for graphing some metrics from my heatpump.

the query i use is:

> returnFlow = from(bucket: “Nibe”)  
> |\> range(start: v.timeRangeStart, stop:v.timeRangeStop)  
> |\> filter(fn: (r) =\> r.\_measurement == “40047” )  
> |\> drop(columns:[“\_start”, “\_stop”, “\_measurement”, “\_field”, “category id”, “designation”, “system id”, “system unit id”, “title”, “unit”])
> 
> flow = from(bucket: “Nibe”)  
> |\> range(start: v.timeRangeStart, stop:v.timeRangeStop)  
> |\> filter(fn: (r) =\> r.\_measurement == “40048” )  
> |\> drop(columns:[“\_start”, “\_stop”, “\_measurement”, “\_field”, “category id”, “designation”, “system id”, “system unit id”, “title”, “unit”])
> 
> deltaT = join(tables:{returnFlow:returnFlow, flow:flow}, on:[“\_time”])

I have tried to “copy” from the article and updated for my use case. But i cannot get it to work, i always get the error " ```  
error in query specification while starting program: this Flux script returns no streaming data. Consider adding a “yield” or invoking streaming functions directly, without performing an assignment

```auto

It seems so simple but ended up as a blocker for me
```