Issue with the Varchar type in postgresql

1

hi im new in grafana and when i try to put the sql in the query editor it bring me this message

Column metric must be of type UNKNOWN, TEXT, VARCHAR, CHAR. metric column name: metric type: VARCHAR but datatype is

betwen the <> is nil
the sql i tried is this

select
now() as “time”,
count(*) as cnt,
estado as metric
from owner.table
group by estado;

if you can help me, i would appreciate you

2

the solution was to put a is not null in the metric

select
now() as “time”,
count(*) as cnt,
estado as metric
from owner.table
group by estado
where estado is not null;