JOIN Nested DISTINCT - sql

Question

I am writing SQL statements with MS Access and I am wondering how I can nest a SELECT DISTINCT statement in my JOIN?
At the moment I am writing 2 queries to get an output (2 steps):
1st query is a simple DISTINCT statement.
2nd query is a JOIN on the query created in 1.
How can I nest a DISTINCT statement in the join in order to perform the action in a single step?
SELECT DISTINCT tblFinalIssuerNames_ReverseRepos.ISIN, tblFinalIssuerNames_ReverseRepos.IssuerCode
FROM tblFinalIssuerNames_ReverseRepos;
SELECT QSel_CollateralReposII.ISIN, QSel_CollateralReposII.MarketValueUSD, QSelDistinctISINs.IssuerCode
FROM QSel_CollateralReposII INNER JOIN QSelDistinctISINs ON QSel_CollateralReposII.ISIN = QSelDistinctISINs.ISIN;
I was thinking about something like the below but the syntax is wrong…
SELECT QSel_CollateralReposII.ISIN, QSel_CollateralReposII.MarketValueUSD, tblFinalIssuerNames_ReverseRepos.IssuerCode
FROM QSel_CollateralReposII INNER JOIN tblFinalIssuerNames_ReverseRepos ON SELECT DISTINCT QSel_CollateralReposII.ISIN = tblFinalIssuerNames_ReverseRepos.ISIN;

Answer 1

I can't test what is allowed and what is not in Access but you can replace QSelDistinctISINs in your query with the query that defines it, by just putting it inside parenthesis and giving it an alias - d below. This is valid SQL syntax:
SELECT
r.ISIN,
r.MarketValueUSD,
d.IssuerCode
FROM
QSel_CollateralReposII r
INNER JOIN
( SELECT DISTINCT
ISIN,
IssuerCode
FROM
tblFinalIssuerNames_ReverseRepos
) d
ON r.ISIN = d.ISIN ;