Grafana showing last value in time series dashboards if the query doesn't return any value

In grafana time series dashboards the grafana is showing the last value if the query doesn’t return any value to it… As I’m using Prometheus data source and I have Oracle SQL query so for example 12-10-22 if the source_name has 3 count and on 13-10-22 if the source name has no count… but on 13-10-22 the grafana shows 3 count still in time series graph and for your information I’m using query exporter and using two transform one is labels to fields and merge

Im expecting if the count is not there it show no data on dashboard not the last value… please suggest what i should do