MySql Workbench中的索引查詢

Question

我需要編寫一個涉及子查詢的查詢並進行索引。 因此，我想出一個查詢來查找一年內組建速度最快的團隊名稱：

SELECT CONCAT(team_long_name, ',', team_short_name) AS TeamName,
       EXTRACT(YEAR FROM date) AS Year,
       buildUpPlaySpeed
FROM team JOIN
    team_attributes
    ON team.team_api_id = team_attributes.team_api_id
WHERE
    (buildUpPlaySpeed,team_attributes.date) in (SELECT 
            MAX(buildUpPlaySpeed),team_attributes.date
        FROM team_attributes
        WHERE team_attributes.date = team_attributes.date
        group by team_attributes.date)
ORDER BY date desc;

索引顯示在date，team_api_id，buildUpPlaySpeed列上。

關於如何進一步降低成本的任何建議？

Answer 1

是。 用聯接替換相關的子查詢：

SELECT CONCAT (
    team_long_name
    ,','
    ,team_short_name
    ) AS TeamName
    ,EXTRACT(YEAR FROM [DATE]) AS Year
    ,buildUpPlaySpeed
FROM team
INNER JOIN team_attributes ON team.team_api_id = team_attributes.team_api_id
INNER JOIN (
    SELECT MAX(buildUpPlaySpeed) maxbuildup
        ,team_attributes.[DATE]
    FROM team_attributes
    WHERE team_attributes.[DATE] = team_attributes.DATE
    GROUP BY team_attributes.[DATE]
    ) x ON buildUpPlaySpeed = x.maxbuildup
    AND team_attributes.DATE = x.[DATE]
ORDER BY [DATE] DESC
;

並且，出於理智的考慮，請不要將列“ date”命名為SQL所使用的列。 非常混淆。

Answer 2

也試試這個

SELECT CONCAT(team_long_name,',',team_short_name) AS TeamName,EXTRACT(YEAR FROM DATE) AS Year,buildUpPlaySpeed
FROM team
INNER JOIN team_attributes ON team.team_api_id = team_attributes.team_api_id
INNER JOIN ( SELECT MAX(buildUpPlaySpeed) maxbuildup,team_attributes.DATE FROM team_attributes
    WHERE team_attributes.DATE = team_attributes.DATE
    GROUP BY team_attributes.DATE  ) t1
where buildUpPlaySpeed = t1.maxbuildup AND team_attributes.DATE = t1.DATE ORDER BY DATE DESC;