ランクに基づくSql結果の返信

Question

特定の国とスポーツの上位3名の選手のリストを返すにはどうすればいいですか？

ATHLETES 

+------------+-----------------+---------------+-------------------------+ 
| idATHLETES | ATHLETENAME  | TEAMS_idTEAMS | TEAMS_COUNTRY_idCOUNTRY | 
+------------+-----------------+---------------+-------------------------+ 
| JG   | JUSTIN GATLIN | USA-TF-MEN | USA      | 
| MS   | MARIA SHARAPOVA | RUS-WTA  | RUS      | 
| SW   | SERENA WILLIAMS | USA-WTA  | USA      | 
| UB   | USAIN BOLT  | JAM-TF-MEN | JAM      | 
| VW   | VENUS WILLIAMS | USA-WTA  | USA      | 
+------------+-----------------+---------------+-------------------------+ 

EVENTS 

+------------+---------------+---------------------+------------------------+----------------------------------+--------------------------+ 
| idEVENTS | EVENTNAME  | ATHLETES_idATHLETES | ATHLETES_TEAMS_idTEAMS | ATHLETES_TEAMS_COUNTRY_idCOUNTRY | VARIOUS_SPORTS_SPORTS_ID | 
+------------+---------------+---------------------+------------------------+----------------------------------+--------------------------+ 
| ATH  | ATHLETICS  | JG     | USA-TF-MEN    | USA        | TRACK-AND-FIELD   | 
| ATH  | ATHLETICS  | UB     | JAM-TF-MEN    | JAM        | TRACK-AND-FIELD   | 
| TEN  | TENNIS  | MS     | RUS-WTA    | RUS        | WOMENS_TENNIS   | 
| TEN  | TENNIS  | VW     | USA-WTA    | USA        | WOMENS_TENNIS   | 
| TEN-DOUBLE | TENNIS DOUBLE | SW     | USA-WTA    | USA        | WOMENS_TENNIS   | 
| TEN-DOUBLE | TENNIS DOUBLE | VW     | USA-WTA    | USA        | WOMENS_TENNIS   | 
+------------+---------------+---------------------+------------------------+----------------------------------+--------------------------+ 

RESULTS 

+-----------+-------------+--------+-----------------+----------------------------+-------------------------------+---------------------------------------- 
+-----------+-------------+--------+-----------------+----------------------------+-------------------------------+-----------------------------------------+---------------------------------+ 
| idRESULTS | STATUS  | MEDALS | EVENTS_idEVENTS | EVENTS_ATHLETES_idATHLETES | EVENTS_ATHLETES_TEAMS_idTEAMS | EVENTS_ATHLETES_TEAMS_COUNTRY_idCOUNTRY | EVENTS_VARIOUS_SPORTS_SPORTS_ID | 
+-----------+-------------+--------+-----------------+----------------------------+-------------------------------+-----------------------------------------+---------------------------------+ 
| results1 | DID-NOT-WIN | SILVER | TEN    | MS       | RUS-WTA      | RUS          | WOMENS_TENNIS     | 
| results1 | WON   | GOLD | TEN    | VW       | USA-WTA      | USA          | WOMENS_TENNIS     | 
| results2 | DID-NOT-WIN | BRONZE | ATH    | JG       | USA-TF-MEN     | USA          | TRACK-AND-FIELD     | 
| results2 | WON   | GOLD | ATH    | UB       | JAM-TF-MEN     | JAM          | TRACK-AND-FIELD     | 
| results3 | WON   | GOLD | TEN-DOUBLE  | SW       | USA-WTA      | USA          | WOMENS_TENNIS     | 
| results3 | WON   | GOLD | TEN-DOUBLE  | VW       | USA-WTA      | USA          | WOMENS_TENNIS     | 
+-----------+-------------+--------+-----------------+----------------------------+-------------------------------+-----------------------------------------+---------------------------------+ 

VARIOUS_SPORTS 

+-----------------+----------------------+ 
| SPORTS_ID  | SPORTS_NAME   | 
+-----------------+----------------------+ 
| TRACK-AND-FIELD | MENS TRACK AND FIELD | 
| WOMENS_TENNIS | WOMENS TENNIS  | 
+-----------------+----------------------+ 

THE_COUNTRY 

+-----------+-------------+ 
| idCOUNTRY | COUNTRYNAME | 
+-----------+-------------+ 
| JAM  | JAMAICA  | 
| RUS  | RUSSIA  | 
| USA  | USA   | 
+-----------+-------------+ 

THE_TEAMS 

+------------+----------------------------------+-------------------+ 
| idTEAMS | TEAMNAME       | COUNTRY_idCOUNTRY | 
+------------+----------------------------------+-------------------+ 
| JAM-TF-MEN | jamaican track and field men  | JAM    | 
| RUS-WTA | russian women tennis association | RUS    | 
| USA-TF-MEN | usa track and field men   | USA    | 
| USA-WTA | usa womens tennis association | USA    | 
+------------+----------------------------------+-------------------+ 

私はこのコードをこれまで持っていますが、これは必要な出力を返しませんか？

SELECT idATHLETES, ATHLETENAME, TEAMS_COUNTRY_idCOUNTRY, COUNTRYNAME FROM 
athletes 
JOIN EVENTS ON idATHLETES = idEVENTS 
JOIN teams ON TEAMS_idTEAMS =idTEAMS 
JOIN country ON COUNTRY_idCOUNTRY = idCOUNTRY 
JOIN RESULTS ON ATHLETES_idATHLETES = EVENTS_ATHLETES_idATHLETES 

WHERE EVENTS_VARIOUS_SPORTS_SPORTS_ID = 'WOMENS_TENNIS' AND EVENTS_ATHLETES_TEAMS_COUNTRY_idCOUNTRY ='USA' ; 

Answer 1

アスリートでグループ化し、メダルを数えることを検討してください。

SELECT idATHLETES, ATHLETENAME, TEAMNAME, COUNTRYNAME 
     , MEDALS = SUM(CASE WHEN MEDALS IS NULL THEN 0 ELSE 1 END) 
     , SCORE = SUM(CASE MEDALS WHEN 'Gold' THEN 3 
       WHEN 'Silver' THEN 2 
       WHEN 'Bronze' THEN 1 
       ELSE 0 END) 
     , GOLD = SUM(CASE MEDALS WHEN 'Gold' THEN 1 ELSE 0 END) 
     , SILVER = SUM(CASE MEDALS WHEN 'Silver' THEN 1 ELSE 0 END) 
     , BRONZE = SUM(CASE MEDALS WHEN 'Bronze' THEN 1 ELSE 0 END) 
FROM ATHLETES 
JOIN TEAMS ON TEAMS_idTEAMS = idTEAMS 
JOIN COUNTRY ON COUNTRY_idCOUNTRY = idCOUNTRY 
JOIN RESULTS ON ATHLETES_idATHLETES = EVENTS_ATHLETES_idATHLETES 
WHERE EVENTS_VARIOUS_SPORTS_SPORTS_ID = 'WOMENS_TENNIS' 
AND EVENTS_ATHLETES_TEAMS_COUNTRY_idCOUNTRY ='USA' 
GROUP BY idATHLETES, ATHLETENAME, TEAMNAME, COUNTRYNAME 
ORDER BY SUM(CASE WHEN MEDALS IS NULL THEN 0 ELSE 1 END) DESC 
LIMIT 3 

あなたはあなたにORDER BY句を変更することで、そうすることができ、各メダルに異なるポイントを割り当てる必要がある場合：代わりにあなたが値を保持するテーブルを作成することができ

ORDER BY SUM(CASE MEDALS WHEN 'Gold' THEN 3 
       WHEN 'Silver' THEN 2 
       WHEN 'Bronze' THEN 1 
       ELSE 0 END) 

。