TimescaleDB metric grouping

I try to migrate some metrics to timescale db.

Have a simple table:

CREATE TABLE history.db_audit
(
id bigint NOT NULL,
db_user character varying(255) COLLATE pg_catalog.“default”,
db_timestamp timestamp with time zone NOT NULL,
db_id bigint,
db_name character varying(255) COLLATE pg_catalog.“default”,
db_table character varying(255) COLLATE pg_catalog.“default”,
db_value_current jsonb,
db_value_changed jsonb,
db_version bigint,
db_tx_id bigint,
db_action character varying(255) COLLATE pg_catalog.“default”,
db_apm_trace_id character varying(1024) COLLATE pg_catalog.“default”,
db_apm_span_id character varying(1024) COLLATE pg_catalog.“default”
)

I want to graph all my groupings in a single graph without repating it.

For that purpose I am using the query below in grafana

SELECT
__timeGroup("db_timestamp",'1m') as time, count(id) AS "count", db_action, db_name, db_table FROM history.db_audit WHERE __timeFilter(db_timestamp) AND db_name in ($DBName) and db_table in ($TableName) and db_action in ($Action)
GROUP BY time,db_action,db_name,db_table
ORDER BY time

But get in grafana the error

Value column must have numeric datatype, column: db_name type: string value: container_db

If I format the query as Table then the query works but not my grouping of graph es expected.

What I am missing ?

Grafana Version 7.0.3
TimeScalDB Version: 1.7