Question

I am programming an application to keep score for darts. I’ve created a relational database as the following:

GameInformation
gameId | numberOfPlayer | totalInnings | gameType
0 | 2 | 13 | 0
1 | 2 | 14 | 0
2 | 2 | 20 | 0
3 | 3 | 16 | 0

PlayersByGame
gameId | playerId | innings | mpr
0 | 0 | 13 | 1.538
0 | 1 | 13 | 1.651
1 | 0 | 14 | 1.500
1 | 1 | 14 | 2.012
2 | 0 | 20 | 1.658
2 | 2 | 20 | 2.123
3 | 2 | 16 | 2.001
3 | 1 | 16 | 1.325
3 | 0 | 16 | 1.001

Players
Name | Id
Dainon | 0
Andy | 1
Keith | 2

I’m familiar with simple SQL queries but and not sure how to get the number of games played by a player (Dainon) who played against a player (Andy) without the games that have more than 2 players and where only Dainon and Andy played against each other. At the time of the query, I have both Dainon and Andy’s player IDs.

Could anyone provide any insight as to how I write a SELECT statement to do that.

I’ve started with wrong queries such as the following:

SELECT * FROM PlayersByGame WHERE playerId LIKE 0 and playerId LIKE 1;


SELECT gameId, numberOfPlayers, totalInnings, gameType
FROM GameInformation
WHERE (numberOfPlayers = 2)
UNION
SELECT gameId, playerId, innings, mpr
FROM PlayersByGame
WHERE (playerId = 0)
UNION
SELECT gameId, playerId, innings, mpr
FROM PlayersByGame AS PlayersByGame_1
WHERE (playerId = 1)

Thank you, I appreciate any of your assistance!

Answer 1

Try this.
Click her for Sqlfiddle version of it

select count(*) as NumOfGames
from
(
select gameid,count(*)
from 
(
    select gameId,playerId
    from PlayersByGame
    where gameId in
    (
        SELECT gameId from GameInformation
        where numberOfPlayer =2
    )
    AND
    playerId in
    (
        select id from Players
        where Name in('Dainon','Andy')
    ) 
) as A
group by A.gameId
having count(*) =2
) as B