# Executing expression on queries containing grafana dashboard's variable

**URL:** <https://community.grafana.com/t/executing-expression-on-queries-containing-grafana-dashboards-variable/59046>\
**Category:** InfluxDB\
**Created:** [January 14, 2022, 1:09pm UTC](https://community.grafana.com/t/executing-expression-on-queries-containing-grafana-dashboards-variable/59046 "2022-01-14T13:09:51Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![alexserkin](https://sea2.discourse-cdn.com/grafana/user_avatar/community.grafana.com/alexserkin/32/20870_2.png) [@alexserkin](https://community.grafana.com/u/alexserkin)\
**Post date:** [January 14, 2022, 1:09pm UTC](https://community.grafana.com/t/executing-expression-on-queries-containing-grafana-dashboards-variable/59046/1 "2022-01-14T13:09:51Z")

</div>

expression on two queries below gives an error - “expression request error”:

from(bucket: “stat”)  
|\> range(start: v.timeRangeStart, stop: v.timeRangeStop)  
|\> filter(fn: (r) =\> r["\_measurement"] == “sgsnSch4”)  
|\> filter(fn: (r) =\> r["\_field"] == “2G-attch-accept”)  
|\> filter(fn: (r) =\> r[“node”] == “ **${node}** ”)  
|\> filter(fn: (r) =\> r[“servname”] == “gprs”)  
|\> derivative(unit: 1s, nonNegative: true)

from(bucket: “stat”)  
|\> range(start: v.timeRangeStart, stop: v.timeRangeStop)  
|\> filter(fn: (r) =\> r["\_measurement"] == “sgsnSch4”)  
|\> filter(fn: (r) =\> r["\_field"] == “2G-attach-reject”)  
|\> filter(fn: (r) =\> r[“node”] == “ **${node}** ”)  
|\> filter(fn: (r) =\> r[“servname”] == “gprs”)  
|\> derivative(unit: 1s, nonNegative: true)

Expression: $A+$B

Where ${node} is the variable defined for dashboard. If i use node’s name instead of variable, everything is ok.  
What’s wrong with that?