SQL and JSON database - R I have a database (PostgresSQL) which looks like this:

""results"": 
    {""WEBS"": 
        {""WEBS_4"": [{""ip"": ""XXXXX"", ""value"": ""YYYY""}]}}


I would like to access the information of ip.

Then I write the following query in R but doesn't give me any info 

dbGetQuery(conexion,"SELECT 
              data-&gt;'results'-&gt;'WEBS'-&gt;'WEBS_4' -&gt;'ip' as test
                          FROM results;")


And when I write this query

dbGetQuery(conexion,"SELECT                   data-&gt;'results'-&gt;'WEBS'-&gt;'WEBS_4' as test
                          FROM results;")


I get a result like this [{""ip"": ""XXXXX"", ""value"": ""YYYY""}], that is not very useful in R. 

Some other parts of my database are highly nested, so I would like to access those parts which are with the [] signs.

Thanks a lot!
Your WEBS_4 is an array with two elements, so there's no ip element in it, which explains why this fails:

dbGetQuery(conexion,"SELECT 
              data-&gt;'results'-&gt;'WEBS'-&gt;'WEBS_4' -&gt;'ip' as test
                          FROM results;")


You need to get the zeroth element of WEBS_4, and then you can get the ip element of that. This works in a simple PostgreSQL test I set up using psql:

SELECT  data-&gt;'results'-&gt;'WEBS'-&gt;'WEBS_4'-&gt;0-&gt;'ip' as test
                          FROM results;
  test   
---------
 "XXXXX"
(1 row)


So I suspect the relevant R syntax will be (untested):

dbGetQuery(conexion,"SELECT 
              data-&gt;'results'-&gt;'WEBS'-&gt;'WEBS_4'-&gt;0-&gt;'ip' as test
                          FROM results;")