D3 gauge “Cannot read property ‘length’ of undefined”

Dears,

I got the following error whenever I try to make D3 Gauge or Pie Chart while query information from MYSQL DB, but from grafana DB it works…

“Cannot read property ‘length’ of undefined”

below is the table content in MYSQL:

±-------±-----------------------+
| city | count(incident_number) |
±-------±-----------------------+
| Jeddah | 42 |
±-------±-----------------------+