How to write nested query in druid? - druid

Question

I am new to druid. I have worked with mysql databases so far. I want to know, how to write below nested mysql query as a druid query?
Select distinct(a.userId) as userIds
from transaction as a
where
a.transaction_type = 1
and a.userId IN (
select distinct(b.userId) where transaction as b where a.transaction_type = 2
)
I really appreciate your help.

Answer 1

There are couple of things you might be interested to know as you are new to druid.
Druid supports SQL now, it does not support all the fancy and complex feature like SQL does but it does support many standard SQL thing. It also provides the way to write SQL query in druid JSON.
Here's the more detail on that with example:
http://druid.io/docs/latest/querying/sql
Your query is simple enough so you can use druid sql feature as below:
{
"query" : "<your_sql_query>",
"resultFormat" : "object"
}
If you want to build a JSON query for above query and don't want to write entire big JSON then try this cool trick:
Running sql query to broker node with -q and it will print JSON query for you which you can use and then also modify it as necessary, here's the syntax for that:
curl -X POST '<queryable_host>:<port>/druid/v2/?pretty' -H 'Content-Type:application/json' -H 'Accept:application/json' -q <druid_sql_query>
In addition to this, You can also use DruidDry library which provides support to write fancy druid query in Java.