Question

Ok so I’m working on my homework and am having trouble getting the Count function to work correctly.

I am supposed to use “A query that lists all teams that have more than 4 players (in the players table). Include the columns team_id, team_name, and the count of players for that team.”

It is just a simple NHL database our teacher made up for this assignment. There are 18 teams in the teams database and 74 players in the players database.

This is what I have written as of right now:

SELECT teams.team_id, teams.team_name, COUNT(players.team_id) AS PlayerCount 
FROM teams, players
GROUP BY teams.team_id, teams.team_name
HAVING COUNT(players.team_id) > 4;

And when I run that this is the output I get:

TEAM_ID TEAM_NAME                           PLAYERCOUNT            
------- ----------------------------------- ---------------------- 
TBL     Tampa Bay Lightening                74                     
BOS     Bostong Bruins                      74                     
SJS     San Jose Sharks                     74                     
NYI     New York Islanders                  74                     
MIN     Minnesota Wild                      74                     
DET     Detroit Red Wings                   74                     
NYR     New York Rangers                    74                     
PHL     Philadelphia Flyers                 74                     
BUF     Buffalo Bruins                      74                     
PIT     Pittsburgh Penguins                 74                     
DAL     Dallas Stars                        74                     
VAN     Vancouver Canucks                   74                     
WSH     Washington Capitals                 74                     
COL     Colorado Avalanche                  74                     
TOR     Toronto Maple Leafs                 74                     
CLB     Columbus Blue Jackets               74                     
CHI     Chicago Blackhawks                  74                     
ATL     Atlanta Thrashers                   74                     

18 rows selected

I know it’s probably pretty simple to fix, but I can’t find anything that’s like that in my textbook and the Google results I get are either not the same thing or more sophisticated than what I am trying to do.

Any help is greatly appreciated.

Answer 1

You’re doing a cartesian join between the tables.

SELECT teams.team_id, teams.team_name, COUNT(*) AS PlayerCount 
FROM teams, players
WHERE teams.team_id = players.team_id
GROUP BY teams.team_id, teams.team_name
HAVING COUNT(*) > 4;