SQL Query that counts grouped by results not working as intended - mysql

Question

My goal is to get a table that counts the correct answers from a game.
For example I want this
| G.Name | E.Action
| game 1 | correctAnswer
| game 1 | correctAnswer
| game 2 | correctAnswer
| game 3 | correctAnswer
| game 3 | correctAnswer
to become this
| G.Name | Count(*)
| game 1 | 2
| game 2 | 1
| game 3 | 2
the problem is that im getting this instead:
| G.Name | Count(*)
| game 1 | 5
| game 2 | 5
| game 3 | 5
where 5 is the sum of 2+1+2
This is my query
SELECT G.Name, Count(*)
FROM enduser EU
INNER JOIN prescription P
ON EU.UserRefID = P.EndUserRefID
INNER JOIN prescriptiongame PG
ON PG.PrescriptionRefID = P.PrescriptionID
INNER JOIN games G
ON G.GameID = PG.GameRefID
INNER JOIN session S
ON S.PrescriptionRefID = P.PrescriptionID
INNER JOIN entries E
ON E.SessionGameRefID = S.Session
WHERE P.EndUserRefID = 889
AND E.Action = 'correctAnswer'
GROUP BY G.Name
ORDER BY G.Name
How can I solve this issue, when I googled people are using the same method but they get good results
Thanks in advance

Answer 1

I'd bet money that one of your joins is inflating the result. Strip your query down to just the critical tables: prescription, session, and entries. Do you still get excessive results? If not, try adding joins back in, one at a time, until you get over-counting.

Answer 2

Your joins are somehow multiplying the number of rows. This happens when you join tables along different dimensions that are not related to each other. This is a common problem, but I don't understand your data structure so the following is a best-guess.
Your example can be fixed by using count(distinct) on something. So try this:
SELECT G.Name, Count(distinct SessionGameRefID)
Should there be a relationship between session and game?
I wonder if this simplification of your query would fix the problem (it removes the first two tables):
SELECT G.Name, Count(*)
FROM prescriptiongame PG
INNER JOIN games G
ON G.GameID = PG.GameRefID
INNER JOIN session S
ON S.PrescriptionRefID = PG.PrescriptionRefID
INNER JOIN entries E
ON E.SessionGameRefID = S.Session
WHERE PG.EndUserRefID = 889
AND E.Action = 'correctAnswer'
GROUP BY G.Name
ORDER BY G.Name;

Answer 3

supposing all the joins are needed try this query:
SELECT G.Name, Count(G.Name)
FROM enduser EU
INNER JOIN prescription P
ON EU.UserRefID = P.EndUserRefID
INNER JOIN prescriptiongame PG
ON PG.PrescriptionRefID = P.PrescriptionID
INNER JOIN games G
ON G.GameID = PG.GameRefID
INNER JOIN session S
ON S.PrescriptionRefID = P.PrescriptionID
INNER JOIN entries E
ON E.SessionGameRefID = S.Session
WHERE P.EndUserRefID = 889
AND E.Action = 'correctAnswer'
GROUP BY G.Name
ORDER BY G.Name

Answer 4

select G.Name , count(*) from enduser EU, prescription P,prescriptiongame PG ,
games G ,session S ,entries E where P.EndUserRefID = 889 and E.action='correctAnswer' and (EU.UserRefID = P.EndUserRefID) and (PG.PrescriptionRefID = P.PrescriptionID) and (G.GameID = PG.GameRefID) and (S.PrescriptionRefID = P.PrescriptionID) and (E.SessionGameRefID = S.Session)
GROUP BY G.Name
ORDER BY G.Name