I have 2 queries running on two diffrent databases in grafana

Query 1 on DB 1

select key_1, field_1_2, filed_1_3
from table_from_db1

Query 2 on database 2

select key_1, fiedl2_2, field_2_3
from table_from_db2
where key_1  in (key_1 from query 1)

out put
key_1 ,field_1_2, filed_1_3, fiedl2_2,field_2_3

challange – query 1 reurns more than 1000

I looked at few transform and join by field makes sence but i have to pass key_1 to second query is stopping me.
I created variable but limitaion of 1000 in frm is causing issues.