SQL code in Access says error in FROM clause - sql

Question

SELECT
p.Name,
p.Age,
MAX(COUNT(m.winTeam_ID) / (COUNT(m.winTeam_ID) + COUNT(m.lossTeam_ID)))
FROM Players AS p
INNER JOIN Teams AS t
ON t.ID = p.Team_ID
INNER JOIN Matches AS m
ON m.Team_ID = t.ID
GROUP BY
p.Name,
p.Age;

Answer 1

I can suggest the following query:
SELECT TOP 1
p.Name,
p.Age,
COUNT(m.winTeam_ID) / (COUNT(m.winTeam_ID) + COUNT(m.lossTeam_ID))
FROM (Players AS p
INNER JOIN Teams AS t
ON t.ID = p.Team_ID)
INNER JOIN Matches AS m
ON m.Team_ID = t.ID
GROUP BY
p.Name,
p.Age
ORDER BY
COUNT(m.winTeam_ID) / (COUNT(m.winTeam_ID) + COUNT(m.lossTeam_ID)) DESC;
This fixes the syntax problem with your joins. It also interprets the MAX as meaning that you want the record with the maximum ratio of counts. In this case, we can use TOP 1 along with ORDER BY to identify this max record.

Answer 2

MS Access requires strange parentheses when you have more than one join. In addition, MAX(COUNT(m.winTeam_ID)) doesn't make sense. I don't know what you are trying to calculate in the SELECT. Perhaps this does what you want:
SELECT p.Name, p.Age,
COUNT(m.winTeam_ID) / (COUNT(m.winTeam_ID) + COUNT(m.lossTeam_ID)))
FROM (Players AS p INNER JOIN
Teams AS t
ON t.ID = p.Team_ID
) INNER JOIN
Matches AS m
ON m.Team_ID = t.ID
GROUP BY p.Name, p.Age;

Answer 3

I think your Matches table shouldn't have a Team_ID And instead you have winTeam_ID and lossTeam_ID!
And also you want to query players of a team with - something like - the best win-rate.
If so, Use a query like this - tested on SQL Server only -:
select
p.Age, p.Name, ts.rate
from
Players p
join
(select top(1) -- sub-query will return just first record
t.ID
, sum(case when (t.ID = winTeam_ID) then 1 else 0 end) as wins
, sum(case when (t.ID = lossTeam_ID) then 1 else 0 end) as losses
, sum(case when (t.ID = winTeam_ID) then 1.0 else 0.0 end) /
(sum(case when (t.ID = winTeam_ID) then 1.0 else 0.0 end) + sum(case when (t.ID = lossTeam_ID) then 1.0 else 0.0 end)) as rate
from Teams as t
left join Matches as m
on t.ID = m.winTeam_ID
or t.ID = lossTeam_ID
group by t.ID
order by rate desc -- This will make max rate as first
) as ts -- Team stats calculated in this sub-query
on p.Team_ID = ts.ID;