join 4 tables

[Jerry Duenas]

Good day. I have four tables that I would like to pull data from and create a report without having to query every single table multiple times. Here is the scenario
Table a: poiid, poiref, poictry
Table b: pdref, pddesc,pdmp, pdtool,pdlen,pdod,pdid
Table c: ctryid, ctrycode1,ctrycode2,ctrycode3
Table d: mpid, mplen
poiref = pdref
poictry = ctryid
pdmp = mpid

When I enter poiid I am trying to populate a table that cascades the information from every table. Table a provides the information that table b needs. Table c takes the information from table a. Table d takes the information from table b.
So far I have done:
select * from a where poiid = x;
key1 = rs.getString("pdref");
key2 = rs.getString("poictry");
select * from c where ctryid = key2;
select * from b where pdref = key1;
key3 = rs.getString("pdmp");
select * from d where mpid = key4;
and then I use this information for further processing and passing it to a holding table in java prior to creating reports or displaying on the dashboards.
Is there a way to do a join and pull all of this information. On single query is fine but sometimes we have a range of queries all based on table a. Your assistance in guiding me along this process is greatly appreciated