postgresql: join syntax error when joining 2 select statements - sql

Question

I am querying the aact database from clinicaltrials.gov. The database model is right here: https://aact.ctti-clinicaltrials.org/schema. I have two schemas that I am selecting from (ctgov, proj_cdek_standard_orgs). I am trying to join two select statements. edit: I have now tried aliasing my subqueries, but that still does nothing. I get the following error:
(SELECT ctgov.sponsors.name, ctgov.sponsors.nct_id, ctgov.sponsors.id, ctgov.studies.phase
FROM ctgov.sponsors, ctgov.studies
WHERE ctgov.sponsors.nct_id=ctgov.studies.nct_id) A
FULL [OUTER] JOIN
(SELECT proj_cdek_standard_orgs.cdek_synonyms.id, proj_cdek_standard_orgs.cdek_synonyms.name
FROM proj_cdek_standard_orgs.cdek_synonyms) B
ON
A.name = B.name;
I can do both select statements perfectly fine on their own, but I try the query and I get this error:
ERROR: syntax error at or near "t1" LINE 7: ) t1
What did I do wrong and how do I use joins without getting syntax errors?

Answer 1

Please use below query,
SELECT ctgov.sponsors.name, ctgov.sponsors.nct_id, ctgov.sponsors.id,
ctgov.studies.phase, proj_cdek_standard_orgs.cdek_synonyms.id,
proj_cdek_standard_orgs.cdek_synonyms.name
FROM ctgov.sponsors, ctgov.studies, proj_cdek_standard_orgs.cdek_synonyms
WHERE ctgov.sponsors.nct_id=ctgov.studies.nct_id
and proj_cdek_standard_orgs.cdek_synonyms.name = ctgov.sponsors.name;
But the right way is to use traditional joins,
SELECT ctgov.sponsors.name, ctgov.sponsors.nct_id, ctgov.sponsors.id,
ctgov.studies.phase, proj_cdek_standard_orgs.cdek_synonyms.id,
proj_cdek_standard_orgs.cdek_synonyms.name
FROM ctgov.sponsors
INNER JOIN ctgov.studies
ON (ctgov.sponsors.nct_id=ctgov.studies.nct_id)
INNER JOIN proj_cdek_standard_orgs.cdek_synonyms
ON (proj_cdek_standard_orgs.cdek_synonyms.name = ctgov.sponsors.name);
You can change it to LEFT or FULL OUTER JOIN according to your requirement.

Answer 2

You have to provide an alias to the sub-queries. Also you should not use implicit joins as you have used in first subquery, always try to use explicit joins.
SELECT
*
FROM
(
SELECT
ctgov.sponsors.name, ctgov.sponsors.nct_id, ctgov.sponsors.id, ctgov.studies.phase
FROM ctgov.sponsors
JOIN ctgov.studies
ON ctgov.sponsors.nct_id=ctgov.studies.nct_id
) t1
FULL JOIN
(
SELECT
proj_cdek_standard_orgs.cdek_synonyms.id, proj_cdek_standard_orgs.cdek_synonyms.name
FROM proj_cdek_standard_orgs.cdek_synonyms
) t2
ON
t1.name = t2.name;