MYSQL SUM和INNER JOIN

Question

I want to have the name in the first colomn but i get an error. When i Let P.name out, the query works but I can't see the player name.

Right now I have the following query:

SELECT P.Name, P.Playernr, SUM (F.Amount)
FROM FINES F
INNER JOIN PLAYERS P
ON F.Playernr = P.Playernr
GROUP BY  P.Playernr

Thanks in advance for help

Onno

Answer 1

You should add it to the GROUP BY clause.

SELECT P.Name, P.Playernr, SUM (F.Amount)
FROM FINES F
INNER JOIN PLAYERS P
ON F.Playernr = P.Playernr
GROUP BY  P.Name,P.Playernr

Answer 2

Try this:

SELECT MAX(P.Name) as Name, P.Playernr, SUM (F.Amount)
FROM FINES F
INNER JOIN PLAYERS P
ON F.Playernr = P.Playernr
GROUP BY  P.Playernr

or add P.Name to the Group BY

SELECT P.Name, P.Playernr, SUM (F.Amount)
FROM FINES F
INNER JOIN PLAYERS P
ON F.Playernr = P.Playernr
GROUP BY  P.Name,P.Playernr

Answer 3

When GROUP BY used, only group by column and aggregation function can be projected. Remove P.Name in projection column or add P.Name in GROUP BY

SELECT P.Name, P.Playernr, SUM (F.Amount)
FROM FINES F
INNER JOIN PLAYERS P
ON F.Playernr = P.Playernr
GROUP BY  P.Playernr, P.Name

In other RDBMS, your query produces error.

think about below data:

P.Playernr   P.Name
A         B
A         C
A         D

then, P.Name is not in GROUP BY, which value is produced in SELECT P.Playernr. so, you must use aggregation function or add P.Name in GROUP BY